Methods and devices for deploying and releasing a temporary implant within the body

ABSTRACT

Methods, devices and systems for delivering a device assembly into a gastric or other space within the body, allowing the device to expand to occupy volume within the gastric space and, after an effective period of time, delivering a substance or stimulus to begin breakdown of the expanded device so that it may release from the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/773,516 filed Feb. 21, 2013, which is a non-provisional ofU.S. Provisional Applications Nos.: No. 61/762,196 entitled ThermallyDegradable Biocompatible Constructs and Methods of Degrading filed Feb.7, 2013; 61/601,384 entitled Swallowed Intragastric Balloon Filled viaNarrow Extracorporeal Tube filed Feb. 21, 2012; 61/645,601 entitledDelivery String for Gastrointestinal Applications filed May 10, 2012;61/647,730 entitled Hydrogel Driven Valve filed May 16, 2012; 61/663,433entitled Fluid Transfer Device for Hydrogel Constructs filed Jun. 22,2012; 61/663,682 entitled Hydrogel Driven Valve filed Jun. 25, 2012;61/663,683 entitled Fluid Transfer Device for Hydrogel Constructs filedJun. 25, 2012; No. 61/674,126 entitled Payload Delivery System andMethod filed Jul. 20, 2012; and 61/699,942 entitled System for RapidHydrogel Construct Degradation filed Sep. 12, 2012, the entirety of eachof which is incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention generally relates to the field of devices thattemporarily occlude spaces within the body to provide a therapeuticeffect.

According to 2010 World Health Organization data, 198 million Americansover the age of 15 are above target weight. Of these individuals, 89million are considered overweight (25<Body Mass Index<30) and 109million are considered obese (Body Mass Index>30). Worldwide, more than1.4 billion adults age 20 and over are overweight, and 500 million areobese. Obesity places patients at increased risk of numerous,potentially disabling conditions including type 2 diabetes, heartdisease, stroke, gallbladder disease, and musculoskeletal disorders1,2,3. Compared with healthy weight adults, obese adults are more thanthree times as likely to have been diagnosed with diabetes or high bloodpressure4. In the United States it is estimated that one in fivecancer-related deaths may be attributable to obesity in femalenon-smokers and one in seven among male non-smokers (>=50 years of age).On average, men and women who were obese at age 40 live 5.8 and 7.1fewer years, respectively, than their healthy weight peers.

Gastric bypass surgery is the current gold standard treatment forpatients with a body mass index (“BMI”) of greater than 40. Gastricbypass surgery is also an option for those with a BMI between 35-39 withobesity-related co-morbidities. While gastric bypass surgery results indecreased food consumption and weight loss for a majority of recipients,it requires life-altering, permanent anatomic modifications to thegastrointestinal tract and can result in severe complications. Gastricbypass and related surgical procedures are also expensive, costing about$22,500 (by laparoscopy). For these reasons, only about 250,000 surgicalobesity procedures are performed per year in the US.

For the vast majority of the overweight and obese population for whomsurgical obesity procedures are not appropriate, few efficacious andaffordable interventions are currently available. Diet and exerciseremain the front line approaches to obesity, however this approach hasat best slowed the growth of the epidemic. To date, drug therapies havedose limiting side effects or have lacked meaningful long term efficacy.

One less-invasive intervention that has begun to gain popularity is anintragastric balloon. Intragastric balloons can be placed endoscopicallyor positioned using other methods and generally must be removedendoscopically or rely on the body's natural digestive processes forremoval.

The devices, methods, and systems discussed herein are intended toprovide an effective treatment for obesity. Moreover, the devices,methods, and systems described herein are not limited to any particularpatient population and can even be applied to clinical areas outside ofobesity.

SUMMARY OF THE INVENTION

The present invention relates to devices and methods for occupying aspace within a patient's body. In particular, the devices and methodscan be used within a gastric space. However, the devices and methods canbe used in any part of the body.

The devices described herein can also be used for delivery of drugs,pharmaceuticals, or other agents where such items can be delivered on askin of the device, within a reservoir, in a filler of the device, oranywhere on the device. Such agents can be released over time.

The present disclosure includes medical devices for use with a liquidfiller material and for occupying a space within the patient's body. Inone example such a medical device includes a liquid impermeable surfacematerial forming a device body having an interior reservoir, the devicebody having a deployment profile and expandable to an active profileupon receiving the liquid filler material within the interior reservoir;a liquid tunnel having at least one wall and defining an elongatedpassage, at least a portion of the liquid tunnel extending within theinterior reservoir, and where the at least one wall of the liquid tunnelis pre-disposed to obstruct the elongated passage to prevent fluid flowtherethrough; a fluid conduit having a distal portion located within theelongated passage of the liquid tunnel to create a fluid path throughthe elongated passage for delivery of the fluid into the interiorreservoir, and where the fluid conduit is removable from the liquidtunnel, such that upon removal of the fluid conduit, the at least onewall of the liquid tunnel obstructs the elongated passage to preventfluid therethrough the elongated passage; and a release channel formedby an elongated section of liquid impermeable material, where theelongated section of liquid impermeable material is inverted into theinterior reservoir and temporarily restrained therein, wherein, whentemporarily restrained, the release channel is closed to prevent liquidtransfer to or from the patient's body.

In one variation, the elongated section of liquid impermeable materialforming the release channel comprises a portion of the surface material.The elongated section of liquid impermeable material forming the releasechannel can also comprise at least two layers of the liquid impermeablesurface sealed along at least one edge.

In some variations, the elongated section of material forming therelease channel comprises a tapered shape. Variations of the devices andmethods allow for the device to be used with a gas or other fillermaterial such that the liquid tunnel can simply be a tunnel or amaterial tunnel. However, each variations whether liquid, fluid, ormaterial tunnel offers benefits and disadvantages unique to theconstruction of the device.

Variations of the devices can include a release material thattemporarily restrains the elongated section of material. In one examplethe release material comprises a temperature sensitive material thatdegrades upon reaching a pre-determined temperature. In additionalexamples, the release material comprises a rate of hydrolysis thatcauses degradation of the release material after at least two months.For example, addition of the liquid filler material to the interiorreservoir can initiate the release material in structurally degrading toultimately release the elongated section of material from restraint.

The device described herein can further include an energy storageelement located within the release channel, where the energy storageelement is restrained by a temporary restraint in a compressedconfiguration. In some variations, the energy storage element comprisesan elastically resilient member, on release of the temporary restraint,the elastically resilient member expands the release channel.

Variations of the device can also include an elongated section ofmaterial that is folded to further close the release channel prior tobeing temporarily restrained.

In some variations, an energy storage element is located outside theelongated section of material, where the energy storage elementcomprises a spring.

The at least one wall of the fluid tunnel comprises a first wall and asecond wall, where the first and second wall comprises a section of theliquid impermeable surface material forming the device body.

Variations of the device include a release material that comprises atleast one suture member, where the at least one suture membermechanically couples the fluid conduit to at least one wall of the fluidtunnel. The suture member can be located exterior to the device body. Inadditional variations, the first and a second end of the suture memberextends to the proximal end of the fluid conduit, and a middle portionof the suture member mechanically couples the fluid conduit to the wallof the fluid tunnel, where pulling on the first or second end of thesuture member decouples the fluid conduit from the wall of the fluidtunnel. The suture can also be coupled to at least one weakened portionof the wall of the fluid tunnel such that applying a proximal force onthe suture member detaches the weakened section from the wall of thefluid tunnel to decouple the fluid tunnel from the fluid conduit.

Another variation of a device includes a medical device for use with aliquid filler material and for occupying a space within the patient'sbody. For example, the medical device can include a device body havingan interior reservoir, the device body having a deployment profile andbeing expandable to an active profile upon addition of the liquid fillermaterial into the interior reservoir; an elongate flexible valve havingat least one wall and extending within the interior reservoir, the atleast one wall of the elongate flexible valve being pre-disposed toobstruct fluid flow through the elongate flexible valve; a fluid conduithaving a distal portion removably located within the elongate flexiblevalve to create a fluid path between an exterior of the device body andthe interior reservoir for delivery of the fluid into the interiorreservoir and where removal of the fluid conduit from the elongateflexible valve permits the at least one wall to close to obstruct fluidflow through the elongate flexible valve; and a second fluid passageformed by a second section of material being liquid impermeable, wherethe second section of material is inverted and temporarily restrainedwithin the reservoir, and where freeing the second section of materialfrom restraint permits opening of the second fluid passage to allowegression of fluids from the interior reservoir.

The present disclosure also includes a medical device for use with aliquid filler material for occupying a space within the patient's body.For example such a medical device can include a device body having aninterior reservoir, the device body having a deployment profile and uponreceiving the liquid filler material expands to an active profile; afirst fluid passage defined by at let a first material wall andextending into the interior reservoir, the first material wall of firstfluid passage being pre-disposed to narrow the first fluid passage toobstruct flow therethrough; a fluid conduit having a distal portionremovably located within the first fluid passage to create a fluid pathbetween an exterior of the device body and the interior reservoir fordelivery of the fluid into the interior reservoir and where removal ofthe fluid conduit from the first fluid passage permits the firstmaterial wall to narrow the first fluid passage to obstruct fluid flowtherethrough; and a second fluid passage formed by a second section ofmaterial, where the section of material is inverted and temporarilyrestrained within the reservoir, wherein when temporarily restrained,fluid is prevented from passing from the reservoir through the secondfluid passage and into the patient's body, and where freeing the sectionof material from restraint permits opening of the second fluid passageto allow egression of fluids from the interior reservoir.

The above and other features of the invention including various noveldetails of construction and combinations of parts, and other advantages,will now be more particularly described with reference to theaccompanying drawings and pointed out in the claims. It will beunderstood that the particular method and device embodying the inventionare shown by way of illustration and not as a limitation of theinvention. The principles and features of this invention may be employedin various and numerous embodiments without departing from the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the methods,devices, and systems described herein will become apparent from thefollowing description in conjunction with the accompanying drawings, inwhich reference characters refer to the same parts throughout thedifferent views. The drawings are not necessarily to scale; emphasis hasinstead been placed upon illustrating the principles of the invention.Of the drawings:

FIG. 1A, illustrates an example of a gastric device assembly prior toassuming an active profile.

FIGS. 1B and 1C show partial cutaway views of examples of deviceassemblies for use in occupying space within a body.

FIG. 1D illustrates the variation of the device shown in FIG. 1A as thedevice assembly assumes an active profile.

FIG. 1E shows a device assembly after it is inflated, expanded, orotherwise transitioned to achieve a desired active profile.

FIG. 1F illustrates a state of a device assembly after a physician,patient, or other caregiver desires to initiate release the deviceassembly from the body.

FIG. 2 shows a device assembly or construct in a hydrated or activeprofile whose outer “skin” defines a material reservoir or pocket.

FIGS. 3A to 3E illustrate additional variations of device assemblies 100having various active profiles.

FIG. 4 illustrates a variation of a fluid transfer member also having asealable fluid path for use with the device assemblies described herein.

FIG. 5 shows a variation of a tunnel valve.

FIG. 6A illustrates a partial view of a variation of an invaginatedsection of a skin of a device assembly.

FIGS. 6B through 6D illustrates a partial view of the interior of adevice assembly comprising an invaginated section of the skin furtherhaving energy storage element that assists in opening of the device inresponse to an exogenous trigger.

FIG. 6E provides a schematic illustration of another example of a deviceassembly having a release material located on a surface of the skin.

FIGS. 7A and 7B show one example of an exploded, assembly view of adevice assembly before and after inversion.

FIGS. 7C and 7D illustrate the fabrication of a tapered or conicalinverted section.

FIGS. 7E to 7F illustrate variations where the inverted section includesfeatures to increase retention of a release material to a wall of theinverted section.

FIGS. 7G to 7H illustrate variations where the inverted section includesfeatures to improve the sealing of the inverted section.

FIG. 7I, shows a variation of a spring loaded clamp combined with arelease material for temporarily securing an inverted section.

FIG. 7J shows another variation in which the inverted section comprisesa separate element that is bonded or otherwise affixed to a device body.

FIG. 7K shows a variation where an inverted section comprises anintegral part of material forming the device body.

FIGS. 8A and 8B show an additional variation of a portion of a deviceassembly that provides a control over the fluid permeable path throughotherwise impermeable material surface.

FIG. 9A shows another aspect of devices as described herein comprisingone or more fluid transport members.

FIG. 9B also illustrate a device having a delivery system attachedthereto.

FIGS. 10A and 10B an example of a valve driven by expansion of fillermaterial within a reservoir of the device assembly.

FIGS. 10C and 10D show another variation of a valve.

FIG. 10E shows a hybrid valve wherein each hybrid flow control layer isgenerally rectangular and the impermeable region and permeable regionare triangular.

FIG. 10F shows an exploded view of a valve assembly, a permeable regionin one individual flow control layer may be, for example, a circularregion, and the impermeable region may be an annulus disposed around thecircular permeable region.

FIG. 11A illustrates another variation of a device having a fluidtransport member that comprises a fluid wick that extends into areservoir of the device.

FIG. 11B shows the exterior segment of liquid wick structure immersed ina liquid causing liquid to be drawn into the absorbent wick material ofliquid wick structure and further drawn from the wet wick.

FIG. 12A, shows an exemplary embodiments of liquid wick structurefluidly coupled to a secondary, interior bag, pouch, or other container.

FIG. 12B illustrates another embodiment of a device having multipleliquid wick structures.

FIG. 12C, shows an interior segment of a single liquid wick structurethat is divided into two or more sub-segments.

FIG. 12D shows a wick structure affixed to a portion of the interior ofthe reservoir.

FIG. 13A illustrates a variation of a tunnel valve as discussed abovethat forms a sealable fluid path preventing material from escaping fromthe interior of the device.

FIG. 13B shows a cross sectional view of tunnel taken along line 13B-13Bof FIG. 13A.

FIG. 13C shows the tunnel closing.

FIGS. 13D to 13G show a conduit that is mechanically coupled to a tunnelvalve.

FIG. 13H shows a tunnel valve including a swellable substance betweenlayers of the tunnel valve and a conduit.

FIGS. 13I and 13J shows the use of a spring loaded closure device thataids in sealing of a tunnel valve.

FIG. 14 shows a device assembly compressed to fit within an oral dosageform such as a pill, capsule, sleeve, or other form that enhances theability of positioning the device via ingestion or swallowing withoutthe aid of another medical device.

FIG. 15A shows the swollen mass of various hydrogels after exposure todifferent solutions.

FIG. 15B depicts the swelling performance of poly(acrylamide-co-acrylicacid) superporous hydrogel in solutions at different pHs.

FIG. 15C depicts the swelling performance of a chitosan/poly(vinylalcohol) superporous hydrogel in solutions having varying pH levels.

DETAILED DESCRIPTION OF THE INVENTION

The following illustrations are examples of the invention describedherein. It is contemplated that combinations of aspects of specificembodiments or combinations of the specific embodiments themselves arewithin the scope of this disclosure. While the methods, devices, andsystems described herein are discussed as being used in the stomach orgastric space, the devices, methods, and systems of the presentdisclosure can be can be used in other parts of the body where temporaryocclusion of a space might be required or beneficial. The presentdisclosure is related to commonly assigned to US Publication No.2011/0295299 filed Mar. 2, 2011, the entirety of which is incorporatedby reference.

FIG. 1A, illustrates an example of a gastric device assembly 100. Inthis example, the gastric device assembly or construct 100 can reside ina stomach (typically of a mammal) for an extended period of time. Onebenefit of such a device is that, when partially or fully deployed, theconstruct 100 occupies volume within the stomach to produce atherapeutic effect, e.g., to stimulate the sensation of satiety, andresists passage from the body by normal body function. As illustratedbelow the construct generally comprises three states: a pre-deploymentconfiguration (FIG. 1A); a deployed or active configuration (FIG. 1D,1E); and a release configuration (FIG. 1F). As noted above, the devicecan also be used for therapeutic benefits that do not involve occupyingvolume (e.g., drug delivery, creation of a cavity by separating adjacenttissue, etc.).

FIG. 1A illustrates a variation of the device 100 after placement withina stomach 2. As described herein, the initial configuration of thedevice 100 includes a compact state that allows placement within thebody. The device can be in a pill-type configuration or any other shapethat permits swallowing. Alternatively, the device 100 can be positionedby the use of a scope type device, catheter, or other medicalpositioning device.

For a device used in the digestive tractigastric space, the deviceassembly 100 can be positioned within the body either by naturalingestion or the use of a delivery system (such as a catheter,endoscope, or other medical device). The delivery system can optionallycomprise an oral dosage form, not illustrated, which facilitates theingestion of a relatively large object. In other embodiments the systemcomprises a tether that allows manipulation or control of the placedconstruct from outside of the body. The assembly 100 can also be placedin the stomach by more invasive surgical or endoscopic procedures.

In FIG. 1A, the device 100 is shown immediately after being deployedwithin the stomach 2 and is ready to be activated. As noted herein, thedevice 100 can be deployed in the configuration shown. Alternatively,the device can be contained within a capsule or pill-type casing thatallows for swallowing by a patient. Once swallowed, the casing willreadily dissolve or break down resulting in the configuration shown.Once in place in the stomach, the assembly 100 begins to expand in orderto occupy volume/space within the body. Expansion can occur via manualinflation, including hydration or other activation of a filler material(as shown optionally using a catheter, inflation tube or other deliverysystem), via absorption of body fluids, via remote actuation of asubstance already located within the device assembly, and/or deliveringof a fluid into the assembly, where the fluid itself causes expansion.Variations of the device also include a combination of such expansionmeans.

The variation shown in FIG. 1A includes a member 110 that extends fromthe device 100 to outside of the patient. In this variation shown, themember 110 comprises a fluid transport member that is fluidly coupled toan interior of the device 100 allowing for the delivery of substancesand/or fluids within the device 100. FIG. 1A shows an exemplary fluidsource 90 coupleable to a variation of a fluid transport member 110 suchthat the delivery of fluid causes a filler material 108 within thedevice to expand. In the illustrated example, the fluid transport membercomprises a conduit. However, alternate variations of the devicesdescribed herein include fluid transport members that reside within thepatient's body. Alternate variations of the device 100 also includemembers 110 that function as delivery or positioning systems to ensureproper placement of the device 100 within the body. Such deliverysystems may or may not be fluidly coupled with an interior of thedevice. In variations discussed below, the device can include one ormore fluid transport members that remain within the body but stillconvey fluid into the device 100 to allow the device to assume an activeprofile.

FIG. 1B shows one a partial cutaway view of an example of a deviceassembly 100 for use in occupying space within a body. In thisvariation, the device assembly 100 includes a material surface or skin102 that forms a reservoir or pocket 104 capable of retaining a varietyof substances, including but not limited to fluids, solid substances,semi-solid substances, etc. In the illustrated variation, the reservoir104 holds a filler material 108 such as dehydrated hydrogel granulesthat can swell in size upon the addition of a fluid. However, any numberof substances can be contained within the reservoir 104. Alternatevariations of the device and/or method include assemblies that do notinclude a filler material; rather a filler material can be depositedwithin the reservoir 104 once the assembly is deployed. Alternatively,or in combination, the reservoir can be filled with a gas, liquid orother gel type substance.

In other variations, the device assembly 100 can include an emptyreservoir that can be deployed into the body and subsequently filledwith a filler material or other substance. For example, such variationscan include a liquid filler material that is delivered to the reservoirthrough a conduit. The volume of liquid required to expand the deviceinto a desired active profile can pre-determined. In some variations,the volume can be determined by measuring the back pressure in theconduit or pressure within the reservoir using any number of pressuredetecting elements.

FIG. 1B also illustrates a variation of a sealable fluid path 112coupled to and/or forming part of the fluid transfer member. In thisexample, the sealable fluid path 112 extends outside of the perimeter ofthe skin 102 of the device 100. Additional variations of the device 100can include significantly shortened sealable fluid paths 112. In yetadditional variations, the device assembly 100 can omit the sealablefluid path 112.

As noted herein, the skin 102 includes a release material 106 coupledthereto, where the release material 106 allows for initiating release ofthe assembly 100 from the body shortly after degradation, activation, orbreakdown of the release material. Once the device assembly 100 is inthe active profile, it can remain in the active profile for apre-determined amount of time or until the patient experiences a desiredtherapeutic effect. To initiate release of the device assembly 100 fromthe body, an exogenous material, substance or stimulus is administeredto the patient. The substance can comprise a fluid or other activatingagent having properties that either directly or indirectly act on therelease material to disrupt the barrier and allow the contents of thereservoir to be exposed to the body. For example, the exogenoussubstance can comprise a heated fluid that melts the release material.Alternatively, the exogenous material can change a temperature and/or anacidity of fluids in the stomach such that the enhanced properties ofthe fluids begin to act, either directly or indirectly, upon the releasematerials. In additional variations, the release material can comprise amaterial or materials that effectively form a barrier as discussedherein and are separated or disengaged by the use of an exogenousstimuli (e.g., a magnetic field, ultrasound, IR heating, coherent light,electromagnetic signals, microwave field, etc.).

FIG. 1B also illustrates a variation where the release material 106 isin the form that approximates shape and/or size of the casing used todeliver the device 100 (in this example the release material 106 is in apill shape). One benefit of such a configuration is that the releasematerial 106 can be positioned within the casing without excessivefolding or bending.

FIG. 1C illustrates a sectional view of another variation of a deviceassembly 100. In this variation, the release material 106 binds orotherwise joins edges of the skin from within the reservoir 104. Such aconfiguration protects the release material 106 from the localenvironment of the body (e.g., fluids within the stomach or digestivetract). The release material can still be activated and/or degraded bythe addition of the exogenous material to the body as described herein.However, positioning of the release material within the reservoirpermits the skin 102 to serve as an additional layer of protection toprevent inadvertent release of the device assembly 100. The releasematerial 106 can comprise a layer that binds edges of the skin together.

FIG. 1C also illustrates a variation of a sealable fluid path 112. Inthis example, the sealable fluid path 112 does not extend outside of theperimeter of the skin 102. Additional variations of the device 100 caninclude significantly shortened sealable fluid paths 112. In yetadditional variations, the device assembly 100 can omit the sealablefluid path 112.

FIG. 1D illustrates the variation of the device 100 shown in FIG. 1A asthe device assembly 100 assumes an active profile. An active profileincludes any profile apart from a deployment state and where the profileallows the device to perform the intended effect of occupying volume orspace within the body to produce a therapeutic effect. In theillustrated example, a physician or other medical practitioner deliversfluid via the fluid transport member 110, comprising a conduit 114 inthis variation, and into the reservoir 104 causing a filler material 108to swell. As noted herein, other variations include device assemblieswithout filler material where the conduit 114 simply delivers fluid andor other substances that allow the device assembly to achieve an activeprofile.

When using a conduit 114 that extends outside of the body, a physiciancan deliver a hydrating liquid, such as water or distilled water throughthe conduit 114. Generally, a pre-determined volume of liquid can bemanually or mechanically pumped into the exterior end of the conduitwherein the volume of liquid is pre-determined based on a particularsize of the device assembly or based on a desired active state. In somevariations, the volume of liquid can also depend on the length ofconduit.

The conduit 114 can be used to transfer a substance or into thereservoir 1014 of the device. In the illustrated variation, the conduit114 transfers fluid from outside of the patient's body into thereservoir 104 after deployment of device assembly 100 within the body.Alternatively, or in combination, a fluid transfer member can comprise awick type device that transfers liquids or other fluids from within thebody to the reservoir.

FIG. 1E shows the device assembly 100 after it is inflated, expanded, orotherwise transitioned to achieve a desired active profile. A physiciancan monitor the profile of the device assembly 100 either using a scopepositioned within the stomach (not shown) or non-invasive imaging suchas ultrasound or a radiographic imaging. Alternatively, or incombination, the active profile can be achieved after a pre-determinedvolume of fluid, liquid and/or gas is delivered to the reservoir 104.Furthermore, variations of the device can include one or more markers(such as radiopaque markers) 116 allowing a physician to determineorientation and/or size of the device assembly 100.

As noted above, this particular variation of the assembly 100 includes aconduit 114 that is coupled to the skin 102 through the fluid path 112and extends into the reservoir 104. Alternatively, a conduit 114 can bedirectly coupled to the skin. When the device assembly 100 achieves theactive state the conduit 114 can be pulled from the device assembly 100.For those variations that employ a sealable fluid path 112, withdrawalof the conduit 114 causes the sealable fluid path 112 to collapse or becompressed thereby preventing the contents of the reservoir 104 fromescaping from the device assembly 100. Alternatively, or in combination,the sealable fluid path 112 located within the reservoir 104 can besealed due to the increased pressure within the reservoir. In otherwords, the same pressure within the reservoir 104 that causes expansionof the device 100 also causes the sealable fluid path 112 to close,compress or otherwise reduce in diameter to a sufficient degree thatmaterial is unable to escape from the reservoir through the sealablefluid path 112.

In certain variations, the conduit 114 is held in place in the sealablefluid path 112 by friction alone. Withdrawal of conduit occurs bypulling on the conduit in a direction away from the device 100. Duringthe initial stages of this withdrawal activity the expanded device 100generally moves upwardly with the conduit in the stomach, until theexpanded device 100 reaches the esophageal sphincter. With the deviceassembly restrained from further upward movement by the sphincter, theconduit 114 may then be withdrawn from the fluid path and from thepatient by additional pulling force.

Upon withdrawal of conduit 114 the fluid path effectively seals, asdescribed herein, and prevents migration of fluids or other substancesinto and out of the reservoir. In certain variations the fluid pathseals on its own after removal of a conduit or other member locatedtherein. In additional variations, hydrostatic pressure and/or pressurecaused by the expanded filler acting along the length of the fluid pathcan aid in sealing of the fluid path.

FIG. 1F illustrates a state of the device assembly 100 after a physicianor the patient desires to initiate release the device assembly 100 fromthe body. As discussed above, an exogenous material 120 is deliveredinto the stomach (or other portion of the body as applicable). As theexogenous material 120 (or exogenously activated body fluids) engage therelease material 106, the release material reacts to the conditionscreated by the exogenous material and begins to degrade, melt, breakdown, or otherwise become unstable such that the physical barrier of theskin 102 becomes compromised. As noted above, additional variations ofthe devices can be used with an exogenous stimulus in place of or inaddition to an exogenous material. For example, the exogenous substancecan directly act upon the release material such as providing a substanceat an elevated temperature and/or PH level that causes disruption of therelease material to allow the filler material to interact with thefluids in the stomach and/or to pass from reservoir into the stomach.Alternatively, the exogenous material can interact with fluids withinthe body to directly or indirectly activate and/or degrade the releasematerial.

In alternate variations, the release material, or additional areas onthe skin degrade or become unstable due to the passage of time in thenormal gastric environment. In such cases, the additional areas canserve as a safety mechanism to ensure release of the device after apre-determined period of time. For example, in the variation shown inFIG. 1F, one of the areas of release material 106 can be responsive toexogenous stimulus or exogenous materials while the other releasematerial 106 can break down over time. Alternatively, or in combination,as shown in FIG. 1F an exogenous stimuli can be used in combination withthe exogenous material 120 to cause disruption of the release material.In another variation, the exogenous stimuli 130 can be used to actdirectly on the release material 106 (without any exogenous material) tocause disruption of the release material 106 and to begin the process ofreleasing the device assembly 100 from the patient.

FIG. 1F illustrates the filler material 108 escaping from the reservoir104 as the device assembly 100 decreases from its active profile toallow for passage of the skin 102 and filler material 108 from the body.In certain variations, the consistency of the escaping filler material108 is similar to or closely approximates the consistency of a foodbolus. The matching of the consistency of the filler material tonaturally occurring particles that travels within the body ease thepassage of the filler material 108 through the remainder of thedigestive tract. In certain situations, the instability or degradationof the release material 106 allows bodily fluids to mix with the contentof the reservoir 104, which liquefies the filler material and expeditesreduction of the device assembly 100 from an active profile or state.Although not illustrated, as the device assembly reduces in profile, theperistaltic movement of the muscles in the digestive tract works toextrude materials out of the device 100, allowing for the passage of theskin 102 of the device 100 through the digestive tract until it isultimately excreted from the body. Certain variations of the deviceassembly can be made to have a soft, lubricious and/or malleableconfiguration to aid in passing through the gastrointestinal tract.

FIGS. 1A to 1F are intended to illustrate variations of devices andmethods for occupying space within a patient's body, especially thosedevices for use within a gastric space. However, the principlesdescribed above can be used with any number of variations of the deviceas described below. As noted herein, combinations of differentvariations of devices, as well as the combinations of aspects of suchvariations are considered to be within the scope of this disclosurewhere such combinations do not contradict one another.

In the embodiment shown in FIG. 2 the construct 1000 is in a hydrated oractive profile and comprises a generally oblate spherical shapedstructure whose outer “skin” defines a material reservoir or pocket1010. The reservoir 1010 is bounded by a thin, flexible material surfaceor skin 1013 that encloses an interior volume 1015 for retainingsubstances that maintain the construct in the active profile. In onesuch variation, the reservoir 1010 contains a filler material 1200,which may be a liquid or a semi-solid or gel-like material. In general,the volume of filler material 1200 is initially low, that is, whenconstruct 1000 is in its initial, pre-deployment condition. The volumeof filler material 1200 increases after the construct's deployment.Construct 1000 in FIG. 2 illustrates the fully expanded or active statebut for clarity only a representative portion of filler material 1200 isshown.

The transition from initial, unexpanded state construct 1000 to theactive state can be effected by increasing the volume of filler material1200 enclosed in reservoir 1010. Additionally, the volume can beexpanded through expansion and/or swelling of the filler materialalready inside the reservoir 1010. For example, as was described incommonly assigned U.S. patent application publication numberUS2011/0295299, one exemplary embodiment filler material 1200 in theinitial state is a pre-determined volume of dry hydrogel granules. Thedry hydrogel granules can swell, for example, between 10 and 400 timestheir dry volume when exposed to an appropriate liquid, generally anaqueous solution.

In the variation shown in FIG. 2, once a medical practitioner or userdeploys of the construct 1000 into the stomach, the aqueous liquid inthe stomach migrates into the reservoir 1010 and creates a slurry ofliquid and substantially fully hydrated hydrogel. As is well known,hydrogels absorb water from their surroundings causing swelling of thehydrogel. In the embodiment of FIG. 2, the volume of dry hydrogel ispre-selected to have a fully swollen, unconstrained volume that slightlyexceeds the volume of the reservoir 1010. Under constraint, hydrogelscannot swell to a greater volume than the limits of the constrainingvolume; however, constrained hydrogels can and do exert pressure againstthe constraint. Thus, reservoir 1010 becomes a structurallyself-supporting structure, when filled with an excess of swollenhydrogel (that is, when the unconstrained volume of the swollen hydrogelis greater than enclosed interior volume 1015). In other embodiments,reservoir 1010 is filled and pressurized with other filler. In itsexpanded state, reservoir 1010 can be sufficiently elastic to deformunder external pressure and returns to its pre-deformation shape whenthe pressure is removed. In yet additional variations, the fillermaterial can be selected such that it hardens after a period of time tobecome its own skeletal structure or to support the skin. Such a fillercan be selected to eventually degrade based on the environment in thestomach or digestive tract.

Assemblies 1000 under the present disclosure can comprise a materialsurface or skin 1013 that is substantially impermeable to liquids and/orgases. In these embodiments, filler material 1200 can be, respectively,a liquid or a gas. Additionally, filler material 1200 can be afluid-swellable material such as hydrogel, which, when hydrated, becomesa solid, semisolid or fluid-like gel or slurry. As illustrated in FIG.2, embodiments comprising a substantially impermeable skin 1010 furthercomprise a fluid transport member 1100 that allows for the migration offluid through the skin. In some examples, as noted above, the fluidtransport member includes a sealable fluid path that may or may not becoupled to an additional fluid conduit. In additional variations, thefluid transport member can include a localized liquid transfer member1100 that is disposed in an orifice 1020 through the skin 1013 andfacilitates the migration of fluid between the interior and exterior ofreservoir 1010. One such example can be found in U.S. Provisionalapplication entitled “Resorbable Degradation System” Ser. No. 61/723,794filed on Nov. 8, 2012, the entirety of which is incorporated byreference herein

As noted above, in certain variations, where the device assembly 1000comprises a substantially liquid impermeable material surface, aconstruct 1000 in the expanded active profile can remain in stomach orother portion of the body indefinitely until released. Therefore, asnoted above, devices of the present disclosure can include a releasematerial 1400, which allow the construct 1000 to reduce in size from theactive profile and ultimately pass through the body. Such an activerelease material 1400 configuration allows for on-demand release of theconstruct. As noted above, once activated, degraded, or otherwise madeunstable, the release material allows migration of filler material fromthe reservoir and device assembly. In some variations, activation of therelease material opens a passage in the skin 1013 of the device 1000.Alternatively, or in combination, activation of the release material canresult in reduction of the integrity of the skin forming the barrierabout the reservoir. Once the barrier is compromised, the fillermaterial can safely pass into the body. Regardless of the means, theactivation of the release material and release of the filler materialcollapses the device 1000 leading to egress or removal of the device1000 through the body (in this variation through the lowergastro-intestinal track). As noted above, variations of the devicesdescribed herein include a release material that is activated byexposure to an exogenous substance.

In certain variations, the device assembly 1000, in the active profile,comprises a highly oblate spheroid wherein the skin 1013 can be a thin,film-like material that is soft, tear-resistant, flexible, substantiallyinelastic, and non-self adhesive. Such features can be beneficial for adevice that is to be compressed into a small oral dosage form foradministration. In certain examples, the skin 1013 comprised a 0.0015inch thick polyether polyurethane film. In a simple variation, an oblatespheroid can be created from skins forming an upper material surface anda lower material surface, wherein upper material surface and lowermaterial surface are sealed to each other as shown by seam 1004 in FIG.2. One such means for sealing the device 1000 comprises an ultrasonicweld around the periphery of adjoining materials. As will be describedin more detail below, in a possible assembly method, the upper and lowermaterial surfaces are formed as nominally identical, substantiallydisk-like shapes of material, welded in a band around most of theircircumferences, the assembly is then inverted (turned inside out)through an unwelded section. Once the assembly is inverted, the weldedmaterial forms the seam 1004 that projects.

FIGS. 3A to 3E illustrate additional variations of device assemblies 100having various active profiles. It is understood that the shapes shownin the illustrations disclosed herein are examples of possiblevariations of the device. FIG. 3A illustrates a device 100 having adonut shape (i.e., an oblate shape with an opening 103 in or near acenter of the device assembly 100). FIG. 3B illustrates a deviceassembly 100 having a rectangular or square-like shape. FIG. 3Cillustrates a triangular shaped device assembly 100 In one variation ofthe tunnel valve 1110, as illustrated in FIG. 5, the plurality ofprotrusions 132 that form the device assembly 100. The number anddirection of the protrusions can vary from that shown. FIG. 3E shows avariation of a device assembly 100 having a crescent shape.

The devices shown in FIGS. 3A to 3E also show release materials 106,whether located on an interior of an opening 103 or on an exterior ofthe shape. The variations shown in FIG. 3A to 3E can also include theadditional features of the device assemblies described herein.

Alternatively, the release material can comprise a filament, clip, band,cap, or other structure that mechanically closes the edges of the skin.Further, as described below, a source of stored energy, such as a loadedspring or compressed sponge or other material, may be included in therelease assembly, where such kinetic energy is also released uponactivation of the release material and which may improve the performanceof such assembly.

FIG. 4 illustrates a variation of a fluid transfer member 1100 alsohaving a sealable fluid path 1110 for use with the device assembliesdescribed herein. In this example the fluid transfer member 1100 alsoincludes an elongate fluid conduit, or tube, that passes through atunnel valve that functions as a sealable fluid path 1110. The tunnelvalve 1110 can be positioned in an orifice in the upper 1014 or lower1016 material surfaces or in an opening in a seam 1004 of the deviceassembly. This variation of the tunnel valve 1110 comprises an elongateportion 1022 that extends within the reservoir of the device assembly.In some variations, the tunnel valve can extend beyond the seam 1004 orbeyond the exterior surface of the device assembly as discussed above.

As illustrated in FIG. 4, a portion of the fluid transport memberincludes a tunnel valve 1110 that can comprise two layers sealed alongtheir edges, forming an orifice 1020. In additional variations, thetunnel valve 1110 can comprise a tube structure having a singlecontinuous wall that defines a passage therethrough. In yet additionalvariations, a tunnel valve can include more than two walls. Regardlessof the configuration, the wall or walls of the tunnel valve arepredisposed to occluding or blocking flow through the tunnel valve byobstructing the orifice or passage 1020.

The orifice 1020 forms a fluid path that allows a remainder of the fluidtransport member 1100 to deliver fluids into the reservoir. In thisvariation the fluid transport member 1100 further comprises a conduit.However, as noted herein, the fluid transport member can comprise a wicktype device or any fluid source that allows delivery of fluids into thereservoir of the device. As also noted herein, a variation of the devicecomprises an attachment of conduit 1100 to a portion of tunnel valve1110, wherein the attachment may be direct or indirect and wherein, insome variations the attachment is releasable to permit conduit 1100 tobe detached, withdrawn, or removed from the tunnel valve 1110.Withdrawal or removal of conduit 1110 from orifice 1020 permits thetunnel valve 1110 to prevent egress of fluids or other substances fromwithin the reservoir. Sealing of the tunnel valve 1110 can occur via arise in pressure within the reservoir. Alternatively, or in combination,a number of other mechanisms can result in sealing or closure of theorifice 1020 in the tunnel valve 1110. For example, in additionalvariations the surfaces forming the orifice 1020 can seal upon contactor the length of the tunnel valve 1110 combined with its flexible naturecan simply make it difficult for substances, such as an expandedhydrogel, to travel through the elongated portion 1022 of the tunnelvalve.

FIG. 4 also shows the conduit 1100 extending through the tunnel valve1110 such that it extends into the reservoir. However, in alternatevariations, the device end of conduit 1100 can remain within an interiorof the orifice 1020 of the tunnel valve 1110. In such a variation adistal end of the distal portion of the fluid conduit remains within theelongated passage of the fluid tunnel and can rely on flow pressure topropel the liquid through a portion of the tunnel valve such that thefluid ultimately ends up in the reservoir.

In one variation of the tunnel valve 1110, as illustrated in FIG. 5, thetunnel valve 1110 shaped roughly as the capital letter T, wherein thevertical stem of the T comprises the elongate passage 1022 and whereinthe crossbar of the T, in part, forms an increased attachment surfacethat can be attached to the skin as noted above. As may be seen in FIG.5, tunnel valve 1110 can be disposed through an opening in the seam1004. In other variations tunnel valve 1110 can be formed as pan of theupper 1014 or lower 1016 material surfaces. That is, the templates thatare used to cut the upper and lower material surface layers can includeelongated tabs that correspond to the upper and lower layers of elongatepassage 1022. The seams of said tabs may be sealed during the process ofsealing the upper and lower material surface layers, leaving anunsealed, axially extended orifice in the center of the elongate tabs.

Some examples of materials used to form a tunnel valve include thin,film-like materials. For example, variations include tunnel valvematerials that have properties similar to the material used in materialsurface or skin of the device. Additional materials include but are notlimited to polyurethane, nylon-12, and polyethylene. In certainvariations, Suitable materials typically have a durometer hardness of 80Shore A or softer and are extruded with a glossy finish to enhancecohesion and tackiness. Layers of material in exemplary tunnel valvescan be between 0.001 inch and 0.1 inch thick. In one example a tunnelvalve included a thickness of 0015 inch. The length of the elongateportion 1022 that extends within the reservoir of the device assemblymay be short, for example, 0.1 inch or as long as the diametric width ofthe device assembly.

As discussed above, variations of a device assembly include a releasematerial that is coupled to a portion of the skin to form a barrier toretain substances within a reservoir of the device. FIG. 6A illustratesa partial view of a variation of an invaginated section 126 of a skin102 of a device assembly 100. As discussed herein, the skin 102 caninclude a first surface 122 and second surface 124 joined at a seam 118.The seam 118 can include any number of unjoined sections that areintended to function as release areas 128. In the illustrated example,the release area 128 is bounded by an inwardly directed, or invertedsection 126, of the skin 102. The particular illustrated embodiment ofinverted section 126 is also known as the invaginated section 126, sonamed as it may comprise a tuck, fold, pucker, bulge, extension, etc. inthe skin 102. Alternatively or in addition, the inverted section 126 canbe formed within a first 122 or second 124 surface of the skin 102rather than within a seam 118

The release area 128 of the invaginated section 126 ordinarily forms apassage that is fluidly sealed by a release material 106. The releasematerial can comprise a mechanical closure (such as a staple-typestructure or a filament that ties together the invaginated structure).Alternatively, or in combination, the release material 106 can comprisea temporary seal or other joining of the edges of the invaginatedsection 126. In additional variations, the release material can extendoutwardly from an exterior surface of the skin. In some variations, therelease material 106 is disposed on the invaginated portion 126sufficiently close to the skin to be affected by a temperature increasecaused by delivery of the exogenous substance.

In certain variations, the inverted section 126 forms a release area 128that provides a passage to provide fluid communication between thereservoir and the exterior of the device assembly. This feature allowsrelease of any fluids or material retained within the reservoir to allowthe device to reduce in size and pass from the body. The opening can belocated at the end of the passage, i.e., at the open edge of thematerial that is closed together. Alternatively, the wall forming thepassage can be porous in an area beyond the point at which the invertedsection 126 is bound (e.g., the area disposed inwardly relative torelease material 106).

In additional variations, the inverted section 126 includes an energystorage element that encourages a rapid and more complete opening of therelease area 128. As shown in FIGS. 6B and 6C, variations of theinternal energy storage element 127 can include a solid structure, or astructure that allows passage of fluids. The energy storage element 127can include a compressible elastic material, for example, a latex foam.In some variations internal energy storage element 127 is generallycylindrical with a diameter at least fractionally smaller than thediameter of the passage in the inverted section 126. As shown in FIG.6B, when device 100 is deployed in the body, release material 106 istied firmly around the inverted section 126 at the position of theinternal energy storage element, thereby simultaneously sealing theinvagination and compressing the internal energy storage element. Theenergy storage element can be a solid cylinder or can have a passagetherethrough. The resilience of the elastic material in the internalenergy storage element 127 creates a tensile force in release material106 that is greater than the tension in the release material tie used toseal an invagination alone.

FIG. 6C illustrates the inverted section 126 after an exogenous triggeror inherent degradation causes release material 106 to cease restrainingthe inverted section 126. As illustrated, the release materialstructurally deteriorates to allow opening of the inverted section 126and release the contents of the reservoir. The increased tensiongenerated by the internal energy storage element encourages the releasematerial to break apart sooner, more rapidly, and more completely thanit otherwise would.

As noted above, the internal energy storage element 127 can be acompressible, elastic tube 127 in the form of a hollow cylinder havingan axial fluid passage from one end to the other. The tube, in somevariations, can be glued in place in inverted section 126. In additionalvariations, the elastic tube 127 can comprise a silicone material. Whenthe release material 106 cinches around the area of inverted section 126containing elastic tube 127, the internal passage of tube 127 compressesinwardly and forms a tight seal. Upon release, that is after releasematerial 106 has been degraded by either an exogenous substance or byits organic temporal degradation, elastic tube 127 returns to itsuncompressed state, which includes the hollow, open fluid passage (asshown by FIG. 6C).

One variation of an internal energy storage element is illustrated inFIG. 6C, where the internal energy storage element 127 is a hollowcylinder having an axial fluid passage from one end to the other. Thetube can be glued in place in inverted section 126. In some embodimentselastic tube can be silicone. When filamentary release material 106 iscinched around the area of inverted section 126 containing elastic tube127, the internal passage of tube 127A is compressed inwardly and formsa tight seal.

FIG. 6D illustrates an example of an inverted section 126 that ispleated or folded and restrained by a release material 106. The optionalenergy storage element, if used, is not shown in FIG. 6D for sake ofclarity. However, variations of the devices can include energy storageelements that are located between folds or folded into the invertedsection 126.

In another variation, not illustrated, the energy storage element isdisposed outside of inverted section 126. An external energy storageelement, for example a retaining ring, is used to increase the tensionin the cinched and tied filamentary release material 106. The increasedtension encourages the release material to break apart sooner, morerapidly, and more completely than it otherwise would. A suitableexternal energy storage element may be made using, for example, aspecial order, 5 millimeter diameter, Hoopster® retaining ring,available from Smalley Steel Ring Company, 555 Oakwood Road, LakeZurich, Ill. 60047.

The release area 128 in each of the variations of the inverted section126 is initially sealed or closed off by a release material that iscoupled, directly or indirectly, to a portion of the skin to form abarrier to retain substances within a reservoir of the device. In manyvariations the release material is filamentary. Examples of releasematerials that are available in filamentary form can includePolyglycolide (PGA), Polydioxanone (PDS), Poly(lactic-co-glycolic acid)(PLGA), Polylactide (PLA), Poly (4-hydroxybutyric acid) (P4HB),Polyglactin 910, and Polycaprolactone (PCL).

In such variations, the release material in the expanded device assemblydegrades over time by hydrolysis where the rate of hydrolysis varieswith material selection and liquid filler pH. In variations wherein therelease material is PCL the release material can also degrade byelevating the temperature of the release material since PCL softens,melts, and weakens above a pre-determined temperature. In some cases thepre-determined temperature is greater than normal body temperature.Accordingly, in such variations, the exogenous substance can comprise aheated fluid that can raise the temperature of the PCL without causinginjury to the adjacent areas of the body. As the PCL release materialdegrades, the structural integrity of the joined region of the releasesection (such as the inverted section 126) decreases. In one example,the release material is a modified PCL, wherein the modificationcomprises lowering the melting point of unmodified PCL from its normalmelting temperature to a human-tolerable temperature.

Examples of the release material can include poly(caprolactone) or PCL.In such variations, PCL softens, melts, and weakens above apre-determined temperature. In some cases the pre-determined temperatureis greater than normal body temperature. Accordingly, in suchvariations, the exogenous substance can comprise a heated fluid that canraise the temperature of the PCL without causing injury to the adjacentareas of the body. As the PCL release material degrades, the structuralintegrity of the joined region of the release section (such as theinvaginated section 126) decreases. In one example, the release materialis a modified PCL, wherein the modification comprises lowering themelting point of unmodified PCL from its normal melting temperature to ahuman-tolerable temperature.

For example, an on-demand degrading construct composed of nylon-12 canbe constructed by first fabricating a 1″ circular annulus of 1.5 milPollethane, also known as 55DE Lubrizol 2363 polyether polyurethane(available from Specialty Extrusions Inc. of Royersford, Pa., USA). Acircular degradable patch of poly(caprolactone) (PCL) (with a modifiedmelting point, T_(m), equal to ˜47° C.; available from Zeus IndustrialProducts of Charleston, S.C., USA) can be RF-welded to the Pellethaneannulus, covering the hole, creating a T_(m)-modified PCL patchsurrounded by a rim of Pollethane. The Pollethane rim can then beRF-welded to a sheet of nylon-12, which can then be used for furtherconstruction.

Examples of release materials can include biocompatible manufacturedpolymers. Table 1 is a compilation of the degradation properties ofseveral biocompatible materials that can be extruded or otherwisemanufactured in filamentary form and which also can be predictablydegraded. Some of these materials, poly(vinyl alcohol) are stable in dryenvironments but dissolve very quickly in moist environments. Somebiocompatible polymers, for example co-polymers of methacrylic acid andmethyl-methacrylate, dissolve in liquids having physiologically relevantpHs. For example, they remain stable at pH<7.0 but dissolve at pH>7.0.Other polymers, for example Poly(caprolactone), remain stable at typicalgastric temperatures but melt in seconds at temperatures above apre-determined melting point.

In some variations, polymers that degrade by gradual hydrolysis may beused for the release material. The degradation times of variouspolymers, under various degradation conditions, can range from about 2weeks to about 6 months, where the degradation time depends onparameters such as degradation liquid pH, suture construction (e.g.,stranded or monofilament), and filament diameter. In general, polymerslast longest when exposed to distilled, neutral pH water and degrademore quickly when immersed in acidic or basic pH liquid.

The degradation times for several exemplary materials are tabulated inTable 1. The experimentally determined degradation times in the tablewere determined in simulated use conditions; that is, as illustrated inFIG. 6D, the release material 106 was coupled to an example orsimulation of an inverted section 126 that is pleated or folded.

TABLE 1 Exemplary Release Material Properties Degradation DegradationDegradation Polymer Mode Condition Time Poly(glycolic acid) Gradualhydrolysis Exposure to ~2 weeks water or acid Poly(dioxanone) Gradualhydrolysis Exposure to ~1 to 2 months water or acid 1 PDO 0.9% benzyl 54days alcohol 3-0 PDO distilled water 56 days 4-0 PDO distilled water 60days 4-0 PDO 0.9% benzyl 62 days alcohol 3-0 PDO 0.9% benzyl 65 daysalcohol Poly(lactic-co-glycolic Gradual hydrolysis Exposure to ~1 monthacid) water or acid 3-0 PLGA distilled water 25 days Poly(vinyl alcohol)Rapid dissolution Exposure to any Seconds aqueous solution 4-0 Monocryldistilled water 27 days 2-0 Vicryl 0.9% benzyl 43 days alcohol 2-0Vicryl distilled water 43 days 0 Vicryl distilled water 46 days 0 Vicryl0.9% benzyl 48 days alcohol 1 Vicryl 0.9% benzyl 53 days alcohol 1Vicryl distilled water 53 days Methyacrylic acid Hydrolysis; on-Exposure to Days at near neutral pH methyl-methacrylate co- demand pH-alkaline pH and minutes to hours at polymers dependent alkaline pHdissolution Poly(caprolactone) Hydrolysis; on- Exposure to heat 6 monthsat demand at temperatures less than temperatures melting point, secondsgreater than 60° C. at or above melting point

As the release section opens the reservoir to the surroundingenvironment the opening provides an open path out of the deviceassembly. The open path allows the contents of the device assembly, suchas the filler material, to become exposed to the gastric contents andfreely to exit reservoir. When positioned within the stomach, normalgastric churning assists in emptying the contents of the device assemblyallowing for the entire device along with its contents to pass from thebody. In some variations, the membrane that forms the skin will providelittle or no structural support. This configuration allows the body'snatural squeezing strength to be sufficient to extrude any reasonablyviscous substance out of the device assembly.

FIG. 6E provides a schematic illustration of another example of a deviceassembly 100 having a release material 106 located on a surface of theskin 102. One example of such a release material comprises a degradablepatch 106 that, when degraded, opens the physical barrier surroundingthe reservoir 104 to allow filler material 108 (swollen or unswollen) toexit the device assembly 100. The device assembly 100 comprises a skinmaterial to which release material 106 can be joined (e.g. by heatsealing, RF-welding, impulse heating, or any other means). In certainvariations, the release material/degradable patch 106 comprises amaterial or combination of materials that remains impermeable to waterand hydrogel after deployment and can be degraded “on-demand” inresponse to an exogenous substance or in response to a condition createdwithin the body being the result of the administration of the exogenoussubstance.

In one example, the release material can range from 25 microns thick; upto 2.5 millimeters thick. In another example, release material is amodified poly(caprolactone) with melting point T_(M)=47° C. (availablefrom Zeus Industrial Products of Orangeburg, S.C. USA). In additionalembodiments, degradable patch 106 may be poly(glycolic acid) orpoly(L-lactide acid) (available from Poly-Med, Inc of Anderson, S.C.).

FIGS. 7A and 7B show one example of an exploded, assembly view of adevice assembly 100 (where a fluid transport member is omitted for thesake of clarity). As shown, the device assembly 100 can include amaterial skin comprising two layers of material that form an upper skin122 and a lower skin 124. For clarity in FIGS. 7A and 7B, the exteriorsurface (i.e., the surface which will be on the exterior in the finisheddevice) of each skin 122 and 124 is shown with shading; it will beunderstood that the skin material may be opaque, translucent, tinted, ortransparent. As noted herein, the layers can be joined to form seam 118.Clearly, the presence of a seam is optional and some variations ofdevices under the present disclosure will not include a seam or willhave similar types of joined regions of material to preserve the skin asa physical boundary for the contents of the reservoir. Again, the deviceassembly 100 is shown in the shape that eventually assumes an oblatespheroid shape. However, other shapes are within the scope of thisdisclosure. In one variation, the skin comprises substantially inelasticmaterials 122 and 124 that are joined around a perimeter leavingopenings as discussed herein. It will be understood that, the shape ofthe device referred to as an oblate spheroid for descriptive purposes.In other embodiments wherein one or more devices may be joined tocomprise a multi-bodied assembly, each individual device can beassembled from one or more sheets of film-like material that are cut toa pre-designed shape. FIG. 7A shows the device 100 in an inside-outconfiguration in mid-assembly. Seam 118 is only visible in this view onthe inwardly facing surface of skin 124. As shown, the invaginatedportion 126 can be secured with a filament release material 106 and/or asealing release material 106 located within a release area 128. FIG. 7Billustrates an exploded view of the construct of FIG. 7A after thestructure is inverted and a filler material is inserted into a reservoirformed by the skin materials 122 and 124. Seam 118 is again only visiblein this view on skin 124 and has been folded inward during the inversionprocess.

As described above and further illustrated in the exploded views inFIGS. 7A and 7B, inverted section 126 can be a teat- or nipple-likestructure in which release area 128 is a substantially narrow channelprojecting inwardly into the reservoir of the assembled gastric deviceassembly 100. FIG. 7A illustrates the device assembly during the initialphases of its construction while FIG. 7B illustrates the device assemblyafter inversion of the assembly of FIG. 7A.

Variations of the devices described herein can include inverted sections126 having any number of configurations. For example, as shownschematically in FIGS. 7C and 7D, an inverted section 126 is formed whentwo layers of material 102 are joined together to form a seam 118 havingan extension in the V-shape of a cone- or funnel-like structure. FIG. 7Cshows one layer of the material forming the outer covering or skinjoined together at a seam 118 of the device. This V-shaped extension canthen be cut along the line C-C to produce release area 128 thatultimately allows the inverted section to function to release contentsof the reservoir.

FIG. 7D shows the structure of FIG. 7C after the device has beeninverted such that the V-shaped extension is inverted into the area ofthe reservoir. In this variation, the wall of the inverted structure isformed by the seams 118 of the joined material. These seams 118 form theboundary of the release area or passage. In one variation thefunnel-like structure 126 can be formed by incorporating an acutelyangled, outwardly projecting, flap into two surfaces (e.g., an uppersurface 122 and lower surface 124 of skin 102, see e.g., FIG. 7A). Asnoted herein, the end of the inverted structure 126 is temporarilysecured with a release material 106. In the illustrated variation, therelease material 106 is shown loosely positioned around invertedstructure 126 for exemplary purposes and is not cinched about invertedsection 126. Once cinched, the release material 106 prevents fluid flowthrough the passage 128 until desired or until a pre-determined period.It should be noted that filamentary release material 106 is typicallycinched prior to deployment of the device body.

In certain variations the included angle for the flaps that form theinverted section 126 can be less than or equal to 90 degrees. Similarly,in some variations the included angle for the flap can be greater thanor equal to 45 degrees, although lesser included angles are within thescope of this invention. Again, when device assembly 100 is inverted, asillustrated in FIG. 7D, the outwardly pointing tied flaps of FIG. 7C areconverted into inwardly projecting funnel-like structure 126, comprisingrelease area 128 with release material 106 that is now located insidethe reservoir of the device assembly.

As noted herein, the release area 128 of inverted section 126 ordinarilyforms a passage that is fluidly sealed by a release material 106. Inthose variations, where the release material 106 is a filament that tiesthe inverted section 126 closed to fluidly seal the release area 128,the inverted section 126 can include modifications to improve anchoringof the release material at its intended location. Such anchoring canimprove retention of the release material on the inverted section.

For example, FIG. 7E shows a cross sectional view of an exemplarymodification wherein the edges of the inverted section 126 have anindented or notched region 132 that serves as a defined location for therelease material 106. In FIG. 7E, the region 132 is illustrated ashaving a “V” shaped notch but it will be understood that region B3 mayhave any convenient shape that increases the ability of the releasematerial 106 to maintain the inverted section 126 in a cinchedconfiguration, thereby preventing unintended release of materials withinthe reservoir. In another variation indented region 132 is a waist orsmoothly-varying narrowing of inverted section 126. It should also benoted that filamentary release material 106 is illustrated as looselyencircling inverted section 126 for illustrative purposes only; in anoperational system it would be cinched down tightly to seal release area128.

FIG. 7F shows a second exemplary variation. In this example, the seams118 bounding the inverted section 126 include one or more eyelet regions136 or openings. Eyelet region 136 can be a widening of welded seam 118near the end of inverted section 126. One or more small holes or eyelets134 are disposed in the eyelet region(s), through which eyelets 134filamentary release material 106 is threaded before being cinched andtied. Again, the filamentary release material 106 is illustrated asloosely encircling inverted section 126 for illustrative purposes only.

FIGS. 7G and 7H show additional variations of an inverted section 126where the temporary seal/restraint can be improved by manipulations ofinverted section 126. For example, as shown in FIG. 7G, the open end ofinverted section 126 can be folded back on itself before releasematerial 106 temporarily secures the inverted section 126. FIG. 7G showsinverted section 126 folded back upon itself, where the portion ofinverted section 126 closest to skin 102 is a base section and the endportion of inverted section 126 is a folded section. Release material106 can encircle both layers of inverted section 126 to tightly cinchthe inverted section 126 and to seal release area 128. As previousfigures, filamentary release material 106 is illustrated as looselyencircling inverted section 126 for illustrative purposes only. Althoughnot illustrated in the figure, previous described techniques forsecuring release material 106 to inverted section 126 may be combinedwith folding inverted section 126 back on itself. For example, eyeletregion described above can be added to both base section and the foldedsection. When inverted section 126 is folded the eyelets in base section126A are aligned with the corresponding eyelets in folded section 126B,with filamentary release material 106 threaded through the thusly pairedeyelets.

In another variation, as shown in FIG. 7H, inverted section 126 can betwisted about its elongated axis A before or after being secured withrelease material 106. As illustrated in FIG. 7H, inverted section 126may be twisted several times to form a convenient working length oftwisted material 138. Release material 106 is secured tightly anywherewithin convenient working length 138. The twisted inverted sectionmaterial underneath the release material 106 is compressed into tightlypacked folds, thereby forming a highly effective seal even after therest of the working length of twisted material is released and allowedto untwist. In some variations some of the length of inverted section126 beyond tied release material 106 may be trimmed away.

As illustrated in the side view of FIG. 7I, in another variation,inverted section 126 is sealed with a normally-open, spring loadedmechanical clamp 2100, the clamp being held closed by release material106. Clamp 2100 comprises two loops 2110A and 2110B. The loops arehinged at a common point 2120 and form a jaw that can clamp down oninverted section 126. The two loops that form the jaw are held in tightopposition by release material 106, illustrated as a filamentarymaterial. In this exemplary embodiment, clamp 2100 further comprises atorsional spring 2130 disposed to open the jaws once release material106 has been activated by the exogenous trigger or degraded by gradualhydrolysis.

In other variations inverted section 126 may be sealed with anormally-closed jaw clamp wherein the clamp itself comprises releasematerial 106. In one embodiment the clamp comprises a single, typicallymolded, element with two distinct elongated jaw sections. A section ofmaterial is molded into a flexible region between the two jaws to serveas a hinge, allowing the two jaws to be disposed parallel to each otherand in or nearly in contact along their thusly opposed, elongatesurfaces. The ends of the elongate jaws are equipped with mating, moldedlatch features which, when engaged with one another, keeps the two jawsin their closely opposed configuration. In some variations the opposed,elongate surfaces comprise interdigitated features typically runningparallel to the jaws elongated dimension.

Referring to the exemplary embodiments in FIGS. 6D, 7G, and 7H, the jawclamp may be used in lieu of the filamentary release material 106 toseal inverted section 126. The open clamp may be disposed acrossinverted section 126 with its elongate jaws perpendicular to axis A inFIG. 7H. Closing the jaws down on material 102 seals release area 128and the aforementioned latch features keep the jaws closed until releasematerial from which the clamp has been made is activated by theexogenous trigger or is degraded by gradual hydrolysis.

FIG. 7J shows another variation of a device in which the invertedsection 126 comprises a separate element that is later bonded to skin102. In one variation, shown in FIG. 7J, a circular patch of skinmaterial is formed into a nipple-shaped inverted section 126. Asdiscussed above, the tip of inverted section 126 is removed to createrelease area 128 and the remaining material cinched closed withfilamentary release material 106. The fabricated inverted section 126 isinserted through a hole cut into the upper skin 122, where thedesignation upper skin is only in relationship to the figure, with thefilamentary release material 106 disposed in the interior of the deviceassembly, viz., in the reservoir. The inverted section 126 is bonded toupper skin 122 with either a bonding agent, e.g., a glue, or by otherknown bonding methods, e.g., RF welding.

In yet an additional variation, as shown in FIG. 7K, the invertedsection 126 comprises an integral part of skin 102. During manufacture,inverted section 126 is formed into, for example, bottom skin 124 aspart of the same operation that shapes bottom skin 124 into the desiredhemi-ellipsoid. In some variations bottom skin 124 is joined to top skin122 and inverted section 126 has its tip removed and is cinched and tiedwith filamentary release material 106. The device assembly is theninverted through a working space 160 in top skin 122 and the workingspace sealed. In other variations the inverted section is cinched andtied through working space 160, which is then sealed.

Material Surface or Skin

The type of material or skin will depend upon the intended application.In some variations, a skin will be chosen as a balance of selecting asufficiently thick film-like material that has adequate strength. Forexample in some variations, tear resistance can be preferred to enablethe finished construct to be compression into as low a volume capsule aspossible. The inventors have determined that thin films with a thicknessranging from 0.5 mils to 4 mils are generally suitable. However, thedevices described herein can comprise a greater range of thicknessesdepending upon the particular application, including a range ofthicknesses in different parts of the same construct. In someembodiments, the film-like material must be weldable or adherable toother materials such as might be used in valves 1110, filler materialrelease mechanisms 1400, and/or attachment interfaces as describedherein.

In additional embodiments, the film-like material exhibits lowtransmission rate of filler material, both before and after deviceexpansion. In some embodiment the film-like material exhibits a lowmoisture vapor transmission rate. Additionally, some film-like materialalso exhibits high chemical resistance to the variable conditionsencountered in the stomach. These conditions include low pH, high salt,high detergent concentrations (often in the form of bile salt reflux),enzymatic activities (such as pepsin), and the variable chemistries ofchyme that depend upon the nature and content of consumed food. Forthose devices used in the gastric space, the material must also becomprised of biocompatible materials that can safely be in contact withthe gastric mucosa for the duration of the treatment course.

The devices described herein can use numerous thermoplastic elastomers,thermoplastic olefins and thermoplastic urethanes that can be extrudedor cast into single-layer or multi-layer films which are suitable forembodiments of the gastric device. Example base resins that may beemployed include polypropylene, high-density polyethylene, low densitypolyethylene, linear low density polyethylene, polyester, polyamide,polyether polyurethane, polyester polyurethane, polycarbonatepolyurethane, bi-axially oriented polypropylene, Polyvinylidenechloride, ethylene vinyl alcohol copolymer, and Ethyl Vinyl acetate.Some embodiments comprise single layer films whilst other embodimentscomprise multiple layer films. Other embodiments consist of multilayerfilms including one or more tie layers to prevent layer separation.

In some embodiments, the film-like material may be coated with othermaterials. For example, in some embodiments hyaluronic acid coatings canbe employed to improve softness and lubriciousness. In otherembodiments, coatings such as Parylene® can be applied to improve thechemical resistance of the gastric mucosa-exposed film surface. In someembodiments, wax coatings, PVDC coatings, vacuum-metallization, orParylene® coatings may be applied to the surface of the film to reduceits moisture vapor transmission rate.

In one example, the film-like material used comprised a 1.5 milpolyether polyurethane film. In other embodiments the film-like materialis a 1 mil nylon 12 film or a 1.5 mil LLDPE film. In another example,the film-like material consisted of a multi-layered structure comprisingan outer layer of polyurethane, a middle layer of PVDC or EVOH, and aninner layer of polyurethane.

Filler Material

Generally, a filler material that has a high swelling capacity andachieves a semi-solid consistency is useful to enable the finishedconstruct to be compressed into as low a volume initial state aspossible but still maintain rigidity once expanded. However, unlessspecifically noted, variations of the device can employ a number ofdifferent types or combinations of filler materials. During variousexperiments, it was determined that superabsorbent hydrogel polymerswith a mass:mass swelling capacity of between 100 and 1000 are generallysuitable, where a mass:mass swelling capacity of 100 is defined hereinto mean that 1.0 g of dry hydrogel will absorb water and swell to becomea semi-solid mass of 100.0 g.

Typically, suitable hydrogels swell maximally in the presence ofdistilled water and a number of these hydrogels also de-swell (releasesbound water) in the presence of the variable environmental parametersencountered in the stomach. For instance, parameters such as pH, saltconcentration, concentrations of emulsifying agents (often in the formof bile salt reflux), enzymatic activities (such as pepsin), and thevariable chime chemistries, which depend upon the nature and content ofconsumed food can affect the swelling/deswelling behavior of certainhydrogels. Typical hydrogel swelling times range from between 5 minutesand 1 hour. In one variation, the hydrogel fully swells in under 15minutes and fully de-swells in less than 10 minutes after exposure incertain environments. Many hydrogels are supplied with particle sizesdistributed between 1 and 850 microns. In certain variations, gastricapplications benefit from the use of hydrogel particle sizes distributedbetween 1 and 100 microns. In addition, the hydrogel must also becomprised of biocompatible materials that can be safely in contact withand excreted by the gastrointestinal tract. Examples of suchbiocompatible superabsorbent hydrogel polymers that possess swellingcapacities, swelling times, and de-swelling times suitable forembodiments of gastric construct include poly(acrylic acid),poly(acrylamide), or co-polymers of poly(acrylic acid) andpoly(acrylamide). Another such material that can be used as a fillermaterial is a crosslinked poly(acrylic acid) with particle sizedistribution ranging from 1-850 microns and swelling capacity of 400.

Shapes

As discussed above, certain variations of the device approximate ahighly-oblate spheroid comprising a diameter in the X-Y plane and athickness along the Z-axis as illustrated in FIG. 2. In certainvariations, the expanded dimensions of the device assembly can rangefrom having a diameter between 2 inches and 10 inches. In anotherembodiment, the diameter of the construct is approximately 4.6 inches.The Z-axis thickness can range between 2 inches and 5 inches. However,the device assembly, unless otherwise claimed, is not limited to anyparticular dimension. The data below of construct parameters providesthe experimentally determined dimensions of two constructs having theoblate spheroidal shape.

Parameter Construct 1 Construct 2 Unexpanded diameter (inches) 4.7 5.8′Maximum swollen volume 300 ml 500 ml Expanded diameter (inches) 3.644.63 Expanded thickness (inches) 2.40 2.46

Liquid Transfer Valves

FIG. 8A shows an additional variation of a portion of a device assembly,in other embodiments liquid transfer member comprises a valve 150,wherein valve 150 is disposed in orifice 148 and provides a control overthe fluid permeable path through otherwise impermeable material surface102. In some embodiments valve 150 comprises a multilayer materialstructure composed of regions of permeability 152 juxtaposed againstregions of impermeability 154, whereby fluid may transmigrate betweenthe exterior and the interior of reservoir when the regions ofpermeability 152 and impermeability 154 are not pressed together intight juxtaposition and whereby fluid is inhibited from transmigratingwhen the regions 152, 154 are pressed together tightly. In someembodiments valve 150 is self-closing. That is, valve 150 changes fromallowing fluid transmigration to inhibiting fluid transmigration withoutexternal activation. In one embodiment valve 150 self-closes in responseto the increasing pressure of the expanding filler material orincreasing pressure within the reservoir, for example, swelling hydrogelpressing the regions 152, 154 sufficiently close together to form abarrier.

As noted above, the device assemblies described herein can include awick-type structure that serves as a source to deliver fluids into thereservoir. One example of such a wick includes a filamentary materialcapable of conducting a liquid from one end to the other by capillaryaction. The wick can be used in a stand-alone manner or with a selfclosing valve.

In yet other embodiments liquid transfer mechanism 1100 comprises amechanical valve. Mechanical valves of suitably small dimensions,comprising biocompatible materials, are well known in the art and arecommercially available. A mechanical valve that serves as liquidtransfer mechanism 1100 comprises a one-way or “check” valve designwhich allows fluid to enter reservoir 1010 but prevents fluid fromexiting the reservoir. Alternatively, a mechanical valve that serves asliquid transfer mechanism 1100 may have a normally open state but whichself-closes when internal fluid pressure is greater than external fluidpressure.

FIG. 9A shows another aspect of devices as described herein, forexample, construct 200 can comprise one or more fluid transport members208. As discussed herein, the liquid supply sources 208 are configuredto allow fluid to enter the reservoir to combine with a filler material202 disposed in an unexpanded device assembly 200. In some variations,the fluid transport member 208 can be coupled to a valve 210 thatreduces, blocks or stops transport of liquid when filler material 202 issubstantially hydrated as shown in FIG. 9B. Such a shut off ability isbeneficial as it reduces the likelihood of filler material 202 becomingcontaminated by gastric contents when the device assembly is in theactive profile. Examples of such shutoff-mechanisms are describedherein. FIGS. 9A and 9B also illustrate variations of the deviceassemblies 200 as including a tether 214 or other delivery systemcoupled to an attachment interface 216. FIG. 9A also illustrates twoareas on the skin of the device having sections of release materials206. As noted herein, the release material is responsive to an exogenoussubstance that causes degradation, melting, and/or other instability ofthe release material to allow exposure of the reservoir to the body.This allows the contents of the reservoir to pass from the device andeventually allows for the device to pass from the body.

FIGS. 9A and 9B also illustrate a device 200 having a delivery system214, 216 attached thereto. The delivery system 214, 216 can comprise afilamentary tether 214 that is, generally, attached to the body of thedevice 200 via an interface 216. The attachment interface 216 can bedesigned as a structurally inherent part of the delivery system (i.e.,it cannot be removed from the device body as a separate, stand-aloneitem). Alternatively, the interface 216 can be designed as an elementthat is added on to device 200.

Valves

FIGS. 10A and 10B illustrate one example of a valve driven by expansionof filler material 234 within a reservoir 236 of the device assembly230. The valve 232 is positioned or otherwise disposed in an orifice 238in the material surface or skin 232. This permits fluid to flow into orout of the reservoir 236 when the valve 232 is in an open configuration.In some variations, the orifice 238 comprises, typically, a smallpercentage of the total surface area of material surface 228. Materialsurface 228 is generally impervious or of limited permeability to thefluids in which device 230 is typically immersed. Orifice 238 can be anopening in the otherwise fluid-tight barrier formed by the skin 232.

FIG. 10A also illustrates a pre-determined amount of filler material 234within the reservoir 236. In some variations, the pre-determined amountis generally measured by dry mass. The dry mass of filler material 234is determined by the amount of filler material 234 needed to fill theknown volume of the expanded device 230 when the filler material isfully hydrated. When expanded, the filler material applies a pressurewithin the reservoir 236, which provides a shape-restoring force thatresists externally applied deforming forces.

FIG. 10A also shows valve 232 covering the orifice 238. This variationof the valve 232 includes one or more flow control layers 240 that aidin closing of the valve upon action by the filler material 234. FIG. 10Billustrates expansion of the filler material 234, which increasespressure against the valve 232 and closes the fluid path by compressingthe flow control layers 240

Turning back to FIG. 10A, before filler material 234 expands, valve 232is fully open; that is, it allows fluid to pass through the valve ineither an inward or outward direction. On the other hand, after fillermaterial 234 expands, typically via hydration, the valve 232 fullycloses, as shown in FIG. 10B.

In some embodiments valve 232 comprises a filler material containmentlayer 242. Generally, containment layer 242 is at least partly fluidpermeable and simultaneously able to contain filler material 234, in itsdry or its hydrated state, within construct 230. In some embodimentsfiller material containment layer 242 is also a flow control layer; thatis, a single layer in valve 230 can simultaneously be a part of the flowcontrol function of valve 232 and perform the filler containmentfunction of containment layer 240.

FIGS. 10C and 10D show another variation of a valve 232. In this examplethe valve 232 comprises more than one layer. As shown, this hybrid valve232 comprises two demilunar flow control layers 248, each of the layershaving a hybrid construction being permeable in some generallysemi-circular (viz., demilunar) regions 250 and impermeable in otherregions 252. The impermeable regions 252 of one layer are at leastcomplementary to the permeable regions of the second layer; that is,where one layer has a permeable region the other layer has animpermeable region; generally there will be regions in which both layersare impermeable. Examples of the materials include a permeable patchcomprising a polyester mesh and an impermeable semicircular patchcomprising latex.

As illustrated in FIG. 10D, hybrid valve 232 comprises two substantiallyidentical demilunar hybrid flow control layers, one on top of the other,wherein the two layers are oriented so that impermeable region 252 of afirst hybrid control layer is aligned with the fluid permeable region250 of a second hybrid flow control layer. By symmetry, impermeableregion 252 of second hybrid flow control layer is aligned with the fluidpermeable region 250 of first hybrid flow control layer. The two layersare affixed, typically with glue, around their periphery only, therebyallowing the central areas of the two layers to move apart freely.

It will be obvious to one of ordinary skill in the art that the circularshape of exemplary hybrid valve is a design choice made primarily tosimplify alignment during assembly and installation. The principle ofoperation of a hybrid valve—that the two flow control layers havecomplementary permeable and impermeable regions—is independent of theperipheral shape of the valve or the orifice to which the valve shapeand size is matched. For example, another exemplary hybrid valve isillustrated in FIG. 10E wherein each hybrid flow control layer 248 isgenerally rectangular and the impermeable region 252 and permeableregion 250 are triangular.

Furthermore, permeable region 250 and impermeable region 252 in anyindividual flow control layer need not have identical shapes. Forexample, as shown in FIG. 10F, which shows an exploded view of a valveassembly, a permeable region in one individual flow control layer maybe, for example, a circular region, and the impermeable region may be anannulus disposed around the circular permeable region. However the twolayers of any one hybrid valve must at least have complementarypermeable and impermeable regions; that is, when the two layers areoverlaid there is no permeable area in communication with the exteriorof the device.

In these exemplary embodiments of a hybrid valve, the flow control layerdisposed on the internal side of the valve preferably can also functionas filler material containment layer, with containment being achieved bythe mesh comprising permeable patch. Alternatively, a separate innermostfiller material containment layer must be added to the assembly.

In other embodiments, hybrid flow control layer is fabricated by joininga patch of permeable material and a patch of impermeable edge-to-edge,wherein the joint may be a butt joint, for example, or a lap joint, fora second example, wherein further the outer periphery of the edge-joinedmaterials is designed to fill or cover orifice. In another exemplaryembodiment of a hybrid valve the skin itself can serve as one of theflow control layers.

Wick Permutations

FIG. 11A illustrates another variation of a device 300 having a fluidtransport member that comprises a fluid wick 302 that extends into areservoir 304 of the device 300. Typically, a fluid wick structureconveys fluids from a wet end to a dry (or “drier”) end by capillaryaction. For example, if one end of liquid wick structure 302 is immersedin a liquid whilst the other end of liquid wick structure 302 isdisposed in air, then the liquid moves through the wick structure 302from the immersed end to the “in-air” end, at which end, typically, itwill be absorbed by a filler material. The liquid will continue to flowthrough the liquid wick structure until such time that the “in-air” endis also immersed in liquid (that is, typically, immersed in a puddle ofaccumulated fluid).

Liquid wick structure 302 can optionally comprises a strip or thread ofwater absorbent material, for example, an absorbent matrix of cottonpulp (e.g. as in a sanitary napkin), polyvinyl acetal (e.g., as in aneye wick), polyvinyl alcohol sponge (e.g., as in ear wicks), or othermaterials typically used in, for example, surgical sponges.Alternatively, liquid wick structure 302 can comprise a strip ormulti-strand thread of non-water-absorbing material, for examplecapillary-channeled nylon or polyester, wherein small capillaries areformed between the interior walls of the non-absorbent material. Thewick can also comprise oxidized cellulose (available from Jinan VincentMedical Products Co., Ltd, 122# East Toutuo Street Huangyan, Jinan,Shandong, China). Oxidized cellulose is known to absorb water but, as itis a polysaccharide, eventually solubilize after prolonged immersion inwater.

In one variation, a wick structure 302 can have a substantially circularcross-section, the cross-section generally being greater than 2 mm indiameter and less than 8 mm in diameter, although both greater andsmaller diameter wicks may be appropriate for large or small constructsrespectively, the limits being determined by practicality andconvenience rather than functionality.

Wick structure 302 is designed to convey fluid from the exterior to theinterior of device 300, through an orifice in material surface 306; itslength is preferably the sum of a convenient exterior segment, perhaps 2cm, and an interior segment SKG2100 that is long enough to reach fromorifice 308 to the furthest interior space in which filler material maybe disposed. For some variations of the device, an interior segment ofthe wick 302 is approximately 6 cm, so a typical liquid wick structure302 can be up to approximately 8 cm long. In other embodiments liquidwick structure 302 is between 4 cm and 12 cm in length. However, anyrange of wick length is within the scope of this disclosure.

In one variation, liquid wick structure 302 is inserted through anorifice 308 in device 300, where the device 300 is otherwise impermeableto fluid. Orifice 308 can be designed with a diameter that isapproximately 50% of the diameter of liquid wick structure 302 to ensurethat liquid wick structure 302 fits tightly and securely into orifice308 when liquid wick structure 302 is dry. In some embodiments, orifice308 may also have a diameter that is less than 50% of the diameter ofliquid wick structure 302. The minimum diameter for orifice 308 islimited by constriction of the capillary action in liquid wick structure302. That is, depending on the internal structure of liquid wickstructure 302 and its material properties, too small an orifice willsubstantially shut off the transmigration of fluid through the liquidwick structure.

Alternatively, in some embodiments, orifice 308 may have a diameter thatis greater than 50% of the liquid wick structure diameter, particularlyif liquid wick structure 302 is being securely held by other means. Witha large (greater than 50% orifice of the liquid wick structurediameter), liquid wick structure 302 can be heat-sealed, glued, orotherwise affixed in place in orifice 308 to prevent it from beingdisplaced from its operational disposition.

As illustrated in FIG. 11B, when the construct, or at least the exteriorsegment of liquid wick structure 302 is immersed in a liquid, liquid isinitially drawn into the absorbent wick material of liquid wickstructure 302 and is further drawn from the wet wick material toward thedry wick material until interior segment of liquid wick structure 302 issubstantially saturated. Liquid, on reaching the surface of liquid wickstructure 302 (and in particular the end of interior segment), can beshed by dripping or it may be drawn off by contact with the absorbent,dry filler material. Filler material 306 swells as it absorbs liquid.The pre-determined quantity of dry filler material, when fully expanded,fills the construct to a slightly positive pressure and surroundsinterior segment in a hydrated mass 234. This mass is the functionalequivalent of a liquid bath. With both ends of liquid wick structure 302are immersed in fluid, the liquid wick structure's capillary actionstops or slows considerably, thereby ending fluid movement between theexterior and the interior of construct 300.

As illustrated in FIG. 12A, some exemplary embodiments of liquid wickstructure 302 is fluidly coupled to a secondary, interior bag, pouch, orother container 310 to ensure that interior segment of the wick 302 isin direct contact with filler material 234 located within the container310.

As filler material 234 swells, the container 310 releases fillermaterial 234 into the reservoir of the device 300, where it continues toreceive hydration from liquid wick structure 302. In one embodiment,illustrated in FIG. 12A, secondary bag 310 is water soluble, dissolvingquickly as the partially hydrated hydrogel swells within it. In otherembodiments secondary bag 310 comprises one or more weakened seams, theweakened seams splitting open as the hydrogel swells against it. In yetother embodiments, the entire secondary bag 310 comprises a structurallyweak, permeable material, unable to contain the pressure of the swellinghydrogel. In yet other embodiments, secondary bag 310 comprises seamsclosed with sutures, the sutures being either inherently weak or watersoluble. Any portion of a wick can be coupled to a container, not justthe ends of the wick. For example, a wick can be folded such that thefolded end is positioned within the container.

The wick 302 can be held in place within the container 310 as describedabove for the orifice. Alternatively it may be sealed closed byheat-sealing, gluing, or other means so that the tip of interior segmentis disposed in direct contact with filler material 234.

In some embodiments, liquid wick structure 302 may be fabricated from amaterial that dissolves or degrades in liquid comparatively slowlyrelative to the time it takes for the filler material to fully expand.The material selected for this embodiment maintains its integrity andwicking ability long enough to fully hydrate filler material 234 butthen degrades and disappears once the filler material is fully expanded.Examples of such materials include thin, cellulose-derived, porous wovenor nonwoven materials and ‘ropes’ made of smaller tubes, includingcombinations of nanotubes.

FIG. 12B illustrates another embodiment of a device 300 having multipleliquid wick structures. This embodiment comprises a dual wick structurein which a single wick structure 302 delivers fluid into the reservoirthrough both ends. As shown, a wick is threaded through both sides ofthe skin of the device so that the wick is exposed on both sides. Thesetwo exterior wick segments absorb fluid and convey the fluid between anexterior of the device and the reservoir. Clearly, two or more wickstructures can be used rather than both ends of a single wick structure.

As shown in FIG. 12C, in other embodiments the interior segment of asingle liquid wick structure 302 is divided into two or moresub-segments. Sub-segments of the wick structure 302 can be directed todifferent locations in the reservoir of the device to distributehydration fluid 1105 more efficiently or, as discussed above, each endcan be directed to a secondary container.

In another aspect, a wick structure 302 can be affixed to a portion ofthe interior of the reservoir as illustrated in FIG. 12D. As shownabove, the wick initially extends outside of the device. Upon swellingof the filler material, as the device expands, the section of the wickthat is initially outside the device is pulled into the interior of thedevice assembly because it is affixed or secured to the interior of thereservoir.

Clearly, variations of the wick structure can be combined with otheraspects and features described herein. Moreover, any embodimentdisclosed herein can be combined with aspects of alternate embodimentsor with the embodiment itself. For example, the wicks described hereincan be combined with the valve mechanisms described herein and/or can becombined with the release materials discussed throughout thisspecification.

FIG. 13A illustrates a variation of a tunnel valve as discussed above.As shown, the tunnel valve forms a sealable fluid path that preventsmaterial from escaping from the interior of the device. FIG. 13Aillustrates an example of a device with a tunnel valve forming thesealable fluid path. As shown, device assembly 326 contains a valvemember 330 comprising a liquid impermeable material that can be securelyjoined to the skin 328 in any manner conventionally known or by thosediscussed herein (including, but not limited to gluing, welding, heatsealing, or other means). Examples of materials useful for the tunnelvalve include polyurethane, nylon-12, and polyethylene. The tunnel valve330 can include any number of fluid transport members 332. In theillustrated variation, the valve is coupled to a conduit. However,variations include a wick type device located within the tunnel valve.

FIG. 13B shows a cross sectional view of tunnel 330 taken along line13B-13B of FIG. 13A. As shown the tunnel valve 330 forms part of thefluid transport member 332 allowing transport of fluids between theinterior/reservoir and interior of the device assembly. In certainvariations, the tunnel valve 330 can be detachable from the remainder ofthe fluid transport member 332. Upon removal, the layers of the tunnelvalve 330, as shown in FIG. 13C, close to an extent that the tunnelvalve effectively closes and prevents migration of the filler materialfrom the reservoir. In certain variations, the tunnel valve 330 fullycloses, while in other variations, the tunnel 330 can remain slightlyopen. Variations of tunnel valves include assemblies of an extruded tubeor two layers that are joined by gluing, welding, heat sealing, or othermeans at their two edges. In some variations, the tunnel valve has awall thickness between 0.001″ and 0.1″. One example of a tunnel valveincluded a thickness of 0.0015″. In additional variations, tunnel valvescan be flexible, compressible and/or deformable. In additionalvariations, layers of the tunnel valve can be reopened by the passage astructure (e.g., a conduit or other fluid transport structure).

As noted above, the tunnel valve allows for detachment of the remainderof the fluid transport member at any time, but typically once asufficient amount of fluid is delivered to the device. Removal can occurvia applying tension to a portion of the fluid transport member.Variations of the tunnel valve can employ permeable membranes, filter,or valves placed at the end of the tunnel valve to prevent dry hydrogelor other filler materials from entering the tunnel and affecting theability of the tunnel valve to seal. In some embodiments, the membraneor filter may comprise a permeable fabric such as polyester, nylon, orcellulose. In other embodiments, a valve is placed at the end of tubecomprised of a one-way duckbill or umbrella valve (available fromMiniValve of Oldenzaal, Netherlands). Alternatively, or in addition,filler material 234 can be contained in a container as discussed above,which prevents the filler material from entering the tunnel valve andswelling upon infusion of liquid, thereby clogging the valve.

In additional variations, as shown, for example, in FIG. 13D, a portionof the tunnel valve extends outside the device assembly to form anexternal section 1110B. In some variations, as shown in FIG. 13G,external section 1110 terminates with two unjoined flaps, upper flap1028 and lower flap 1026. In some examples, external section 1110B istypically between 0.1 inch and 0.5 inch long.

In some variations the tunnel valve comprises retaining elements toreleasably hold the conduit in place throughout deployment of the deviceassembly. FIG. 13D illustrates one embodiment for retaining the conduitin a partial cut-away view from the interior of the device assembly.Tunnel valve 1110 comprises an interior section 1110A, which section isdisposed inside the device assembly, and an exterior section 1110B thatextends outwardly from the exterior of the skin. Tunnel valve 1110, asdescribed above, is typically formed by sealing the edges of two layersof membrane material to form sealed seams 1024. In some variationssealed seams 1024 extend all the way to a proximal end 1100B1 and/or adistal end 1110A1 while in other variations the edges of the two layersmay be unsealed for some length inward from proximal end 1110B1 and/ordistal end 1110A1. The relative lengths of the interior and exteriorsections of tunnel valve 1110 have been distorted in the figure forclarity purposes. Typically exterior section 1110B is just long enoughto accept conduit 1100. As has been discussed, conduit 1100 is insertedinto orifice 1020 prior to deployment of the device assembly and is usedto deliver fluid to the reservoir therein to expand device assembly.Conduit 1100 must remain disposed in tunnel valve 1110 until enoughfluid has been delivered to the device assembly to make it too large toinadvertently pass through the pylorus while at the same time conduit1100 must be removable from the device assembly once its deployedprofile has been achieved. Further, it is desirable that conduit 1100also be useful for retrieving the device assembly from the stomach oresophagus in the case of an aborted deployment. In such an aborteddeployment the conduit must be held in the tunnel valve with enoughresistance to withstand the drag on the unexpanded device assembly as itis retrieved upwardly through the esophagus.

A suture 1032, which may be inserted through either or both of interiorsection 1110A or exterior section 1110B, is designed to hold the conduitin the tunnel valve under a wide range of extractive force. Asillustrated in the figure, suture 1032 is stitched through the twolayers of the tunnel valve, simultaneously passing through conduit 1100.The suture is tied to itself on the exterior of tunnel valve 1110. Thesmall punctures in conduit 1100 and tunnel valve 1110 through which thesuture passes are too small to allow any significant loss of liquidfiller.

Once the device assembly has assumed its deployment profile conduit 1100must be withdrawn from tunnel valve 1110. Conduit 1100 is released fromtunnel valve 1110 by the controlled, on-demand degradation of suture1032. As is discussed above certain suture materials can be dissolved orstructurally weakened by exposure to specific exogenous agents notnormally in the gastric environments, or not in the gastric environmentin high enough concentrations to degrade the suture during thedeployment time period. For example, poly(caprolactone) [PCL] softens,melts, and weakens above a pre-determined temperature, T_(M). In somecases the pre-determined temperature can be designed to be greater thannormal body temperature but lower than human's physiologic painthreshold. In such a case, a PCL suture can be degraded by infusingheated liquid (above T_(M)) through conduit 1100 at the end of thedeployment period or by having such liquid consumed orally.

In order to avoid over-filling the device assembly when the heatedliquid is infused through the conduit the hot liquid infusion must startat after a pre-determined volume of un-heated liquid filler material hasbeen infused, where the known capacity of the device assembly, thevolume of fluid residual in the conduit, and the thermal capacity of thesystem are all incorporated into the determination. It should be notedthat if the initial infusion of hot liquid fails to release the conduitby melting the suture, liquid can be withdrawn up the conduit toslightly reduce the volume of the device assembly and a second charge ofhot liquid infused.

In another variation, as depicted in 13E and 13F, conduit 1100 isdetachably joined to one or both double layer sealed seams 1024 oftunnel valve 1110 with a loop of suture material 1032. Suture loop 1032comprises a single long loop which starts and ends at the proximal(e.g., patient's mouth) end of conduit 1100. The loop starts at theproximal end, runs down the interior of conduit 1100, and exits theconduit at a small orifice 1036 that transverses the wall of conduit1100 near the proximal end of exterior section 1110B. After exiting fromorifice 1036, the suture passes through one or two eyelet holes 1034 insealed seams 1024 before returning to orifice 1036. The suture completesits loop by running back up the interior of conduit 1100. The two endsof suture loop 1032 are retained at the proximal end of conduit 1100.

Suture loop 1032 is installed during the manufacture of the deviceassembly and remains disposed in conduit 1110 during infusion of theliquid filler material. Conduit 1110 cannot easily be pulled out oftunnel valve 1110 while suture loop 1032 is in place. Once the deviceassembly has assumed its deployment profile, one end of suture loop 1032may be released while the other end of the loop is pulled outwardly.When at least half the length of suture forming suture loop 1032 haswithdrawn from conduit 1100, the loop is known to be unthreaded from theeyelet hole(s). Freed from the eyelets, conduit 1100 can then bewithdrawn from tunnel 1100.

In some embodiments suture loop 1032 of FIGS. 13E and 13F may be madefrom PCL, in which case conduit 1110 may also be released by meltingsuture loop 1032 through the infusion or ingestion of hot liquid, asdescribed above.

Another variation of fluid transport member 1100 is illustrated in FIG.13G. In this variation sealed seams 1024 stop short of proximal end1110B1, leaving two flaps of material, upper flap 1028 and lower flap1026, where upper and lower are arbitrary designations relating only tothe figure. Upper flap 1028 is prepared with a rip-off tab 1030, whichcomprises the most proximal section of upper flap 1028 and which isdistinguished as the region sectioned off by a tear line 1038 ofdiminished tear-strength material. The tear-strength of tear line 1038may be reduced, for example, by perforations, physical thinning, orchemical application (e.g., partial de-polymerization). In somevariations the tear-strength of tear line 1038 is between 1 and 1.5 lbs.while other variations may have tear-strengths between 0.5 lbs and 2.5lbs.

As illustrated in the figure, conduit 1100 is attached to rip-off tab1030 at spot location 1040, where such attachment may be accomplished,for example, by gluing, melting, or ultrasonic welding. In thisvariation conduit 1100 is detached from tunnel valve 1110 by pullingoutwardly on conduit 1100 with enough force to separate rip-off tab 1030from upper flap 1028 along tear line 1038. Although depicted examplesshow only a single rip-off tab 1030, additional variations include twoor more rip-off tabs, one such tab on each of the two flaps, whereinconduit 1100 is attached to both tabs.

In some embodiments, as depicted in the top view of FIG. 13H, depositinga fluid swellable substance 1046 between the layers of the tunnel valvemay enhance the sealing effectiveness of tunnel valve 1110. Theswellable substance generally remains unswollen while the conduit 1100is installed in the valve. After conduit 1100 removal, swellablesubstance intercepts any liquid or semi-liquid filler material from thereservoir that migrates between the two layers of the nominally sealedvalve. The swellable substance swells in response to any liquidcomponent in the intercepted filler material, thereby blocking furtherfiller material migration through the valve.

The swellable substance 1046 is typically superabsorbent poly(acrylicacid) hydrogel granules or superabsorbent poly(acrylic acid) hydrogelfibers. The swelling ratio of these substances (the mass of waterabsorbed for every gram of substance) is typically greater than 10.

In other embodiments, as depicted in FIG. 13H, orifice 1020 is taperedin one or more regions 1042, 1044, where the dashed line A-A′ indicatesthe skin of the device assembly. The region between the two taperedregions forms a pocket into which the swellable substance may bedisposed. In embodiments with only one tapered region the region willtypically be disposed near distal end 1110A1 and the swellable substance1046 will be disposed to the proximal side of the tapered region.Tapered regions 1042 and 1044, may have a design diameter so that theconduit 1100 fits snuggly through the tapered region. The tapered regioncan then prevent the liquid filler from reaching the swellable substancewhile conduit 1100 is in place. The width of the tapered region istypically the outer diameter or width of the conduit 1100.

In some embodiments the seal of valve 1110 may be enhanced mechanically,as illustrated in FIG. 13I. In this exemplary embodiment a spring-loadedclosure device 2000 is disposed on elongate portion 1022 of valve 1110.Closure device 2000 comprises two, U-shaped loops 2010A, 2010B, loops2010 in this exemplary embodiment being connected at a hinge axle 2015.Each loop 2010 comprises a width comparable to the width of elongateportion 1022 and a length, L, which is the length of each loop 2010extending from hinge axle 2015. For clarity, the loops are illustratedwith exaggerated lengths.

Device 2000 further comprises a spring 2020 or similar energy storageelement. Loops 2010, hinge axle 2015 and spring 2020 are configured toallow spring 2020 to drive loops 2010 into generally adjacent alignmentby rotating one or both loops around hinge axle 2015, as indicated byarrow A in FIG. 13I.

During deployment, conduit 1100 is disposed within orifice 1020,typically extending through substantially the entire length of elongateportion 1022. As previously noted, in some embodiments conduit 1100extends beyond the end of orifice 1020 (as illustrated in FIG. 13I).Closure device 2000 is disposed in its “open-flat” configuration on oraround elongate portion 1022, whereby elongate portion 1022 is threadedthrough closure device 2000 by passing above loops 2010 and below hingeaxle 2015.

Elongate portion 1022 is, by design, stiff enough to hold closure device2000 in its open-flat configuration during deployment. It will be notedthat elongate portion 1022 is stiffened during deployment by thepresence of conduit 1100 since, as described herein, elongate portion1022 is fabricated with two thin layers of a membrane-like materialdesigned to collapse upon themselves while conduit 1100 must be rigidenough to provide an open fluid channel from a patient's mouth to hisstomach.

After deployment, conduit 1100 is withdrawn from orifice 1020. Once theend of conduit 1100 passes the crossbar of loop 2010A, elongate portion1022 is no longer stiff enough to retain loop 2010A in its open-flatconfiguration. Loop 2010A is rotated by torsion spring 2020 in thedirection of arrow A, wrapping the distal end of elongate portion 1022around hinge axle 2015 in the process. Loop 2010A continues rotatinguntil it rests against loop 2010B, simultaneously pressing and sealingthe doubled over elongate portion 1022.

In an alternative exemplary configuration, illustrated in side-view inFIG. 13J, closure device 2000 may be used as a spring clamp only,without the doubling over functionality discussed above. As shown,during deployment closure device 2000 is disposed in its open-jawconfiguration, with elongate portion 1022 inserted into an open jaw 2012formed by loops 2010A and 2010B. During deployment conduit 1100 insideelongate portion 1022 is stiff enough to hold jaw 2012 open; whenconduit 1100 is withdrawn, the force of torsion spring 2015 closes jaw2012, sealing elongate portion 1022.

In another embodiment, not illustrated, an elastic ring provides themechanical assistance for enhancing the seal of valve 1110. The ring isdisposed around on elongate portion 1022 of valve 1110. The ring'smaterial properties and dimensions are selected to substantially sealthe tunnel valve when the valve does not contain conduit 1100. However,when conduit 1100 is positioned within the tunnel valve, the rigidity ofthe conduit resists the sealing force of the elastic ring. The elasticring may be composed of any elastomeric material that is known to bebiocompatible. Examples include silicone, polyurethane, and latex.

Delivery System

As shown in FIG. 14, in certain variations, the device assembly can becompressed to fit within an oral dosage form 352 such as a pill,capsule, sleeve, or other dosage form that enhances the ability ofpositioning the device via ingestion or swallowing without the aid ofanother medical device. In such a case, the device 350 is containedwithin the oral dosage form 352 and can optionally include a tether 356.It should be noted that the conduits described above can also be used asa tether or vice versa. In any case, the tether 356 allows forcontrolling the deployment location of the device 350 within thegastrointestinal tract by manipulation of the tether 356, and finallycompleting the administration procedure by releasing control of thedevice 350, either by releasing the tether 356 for the patient toswallow or, more typically, by detaching the tether from the device 350or oral dosage form. FIG. 14 also shows a tether 356 as having two endsto allow for greater control in positioning the device 350.

In accordance with the delivery method, a medical practitioner,typically a medically trained agent such as a physician, physician'sassistant, or nurse, administers the tethered, encapsulated payload to amammal, herein referred to as the patient. The method comprises thesimultaneous steps of directing the patient to swallow oral dosage formwhile controlling the tether. In some embodiments controlling the tethercomprises the use of a tube to transport liquid into the device, themethod also includes infusion of liquid through the tube using asyringe, pump, or other liquid delivery means. Generally, the step ofcontrolling the tether comprises, firstly, ensuring that the tether'sproximal end is retained exterior to the patient and, secondly,assisting the patient by feeding the tether into the patient's mouth andthroat at a rate compatible with the ingestion of the oral dosage form352. That is, the agent typically adjusts the feed rate of the tether sothe progress of the oral dosage form 352 down the esophagus is notimpeded by tether-induced drag while at the same time the patient doesnot feel the tether is accumulating in his or her mouth. In additionalvariations, the medical practitioner can also use the tether by securingthe section of the tether located outside of the patient's body (i.e.,to a fixture in the room or to a part of the patient).

The method further comprises an optional step of controlling thedelivery distance of the device. The delivery distance is, essentially,how far into the gastrointestinal tract the device is permitted totravel. Typical devices are designed to be deployed in the stomachalthough some devices may be designed to reach only the esophagus whilstother devices can be intended to reach the pylorus or beyond. The stepof controlling the delivery distance is best accomplished with a deviceattached to a marked tether, whereby the length of the ingested tethercorresponds to the instantaneous delivery distance, which length beingdirectly readable from a marked tether. Part of this optional step ofcontrolling the delivery distance is stopping the further ingestion ofthe tether.

In certain variations, the oral dosage form 352 dissolves upon reachingthe stomach and the fluids therein. Once free from the oral dosage form,the device 350 is free to expand into deployed state or an activeprofile. Alternatively, device 350 expands into its active profile uponinfusion of a hydrating fluid through the fluid transfer member.

Filler Material Release

One of skill in the art will note that the human GI tract is uniqueamong the abdominal viscera as it is periodically exposed to very coldand hot substances during routine alimentation. For instance, thetemperature of the stomach is known to increase to 44° C. afteringestion of a hot meal heated to 58° C. but quickly return to core bodytemperature (37-39° C.) in 20 minutes. Moreover, the temperature of thestomach can reach as high as 48° C. for between 1-2 minutes if 500milliliters of 55° C. tap water is consumed rapidly (under 2 minutes) onan empty stomach. Thus, a biocompatible material that could beeliminated by melting would ideally remain stable at core bodytemperature (37-39° C.) but melt in response to a planned interventionthat raised the temperature in the vicinity of the biocompatiblematerial to the material's melting point. In the GI tract, such amaterial would have to withstand daily fluctuations in gastrictemperature (e.g. after ingestion of a hot meal) and remain stable attemperatures between 37° C. and 44° C. but melt in response to a plannedintervention (e.g. consuming 500 milliliter of 55° C. tap water).

In some examples it was noted that one material, polycaprolactone (PCL),has been extruded into a strong monofilament (Japanese publicationJP-A05-59611 A) and has a natural melting point of 60° C., a meltingpoint that is probably not safely usable in human stomachs. However, PCLcan be modified to lower its melting point to more physiologicallyacceptable temperature. Moreover, the modified polymer can still beextruded into a strong monofilament suitable for suturing and stitchingor a film suitable for heat welding to a membrane. PCL filamentarymaterial with reduced melting temperatures (T_(M)) is available fromZeus Industrial Products of Orangeburg, S.C., wherein 60° C.>T_(M)>45°C. by specification.

Delivery of Thermal Exogenous Substance

In some variations the degradable material used as release material 106is allowed to degrade at its natural degradation rate in the mammaliangastric environment. In other variations, degradation is triggered oreffected by the intentional introduction of an exogenous substance 120.In additional embodiments, exogenous substance 120 is introduced orallyand at least partially in a liquid format into the stomach. In thestomach, the exogenous substance 120 mixes with the resident gastricfluid to become an immersing fluid that substantially bathes theconstruct. Alternatively, the exogenous substance 120 may be introducedinto the stomach in a solid state, as in a tablet or capsule, typicallyaccompanied by a liquid, whereby the solid is dissolved and becomes theimmersing fluid, particularly when mixed with gastric fluids. In certainembodiments extra-corporal stimulation of the exogenous substance 120may be used.

In many variations, the release material comprises modified PCLmaterial, either as a thin film for degradable patch or as a filamentarymaterial. In general, modified PCL melts at a specified meltingtemperature, T_(M) and the temperature of the stomach, T_(S), remainsbelow T_(M). The exogenous agent for PCL, therefore, comprises anelevated temperature liquid—at temperature T_(L)—which raises T_(S)above T_(M). The exogenous agent temperature T_(L) needed to raise T_(S)above T_(M) is based on the design details of entire system; that is,the means of delivery of exogenous substance 120, the design of releasematerial (that is, for example, stitches, patch or knot), and thespecified melting temperature, T_(M), of the modified PCL.

For example, an intragastric construct comprising T_(M)=48° C. modifiedPCL will degrade after the rapid ingestion of a large volume of waterwith T_(L)=55° C. Clearly, the location of the PCL release material mayaffect the rate and/or temperature at which the PCL degrades. Theextra-corporal exogenous substance 120 temperature T_(L) is higher thanthe melting temperature of the PCL to account for cooling of theformulation during transit to the stomach and due to mixing with theexistent stomach fluids and for the placement of the release material.In one example, it was found that the rapid ingestion of approximately500 milliliter of 55° C. water elevates stomach temperature T_(S) to atleast 48° C., high enough to dissolve/degrade the modified PCL and allowthe device to open and release its hydrogel contents.

In another example, an intragastric construct comprising with T_(M)=50°C. modified PCL will degrade after rapid endoscopic infusion of 500milliliter tap water with T_(L)=65° C., a temperature that is too hotfor comfortable oral ingestion but which is tolerated by the stomachwhen the liquid is delivered directly to the stomach. Alternatively, theexogenous substance 120 may be delivered directly to the stomach via anasogastric tube, again circumventing the comfort limitations of oralingestion.

In another variation, an exogenous substance can be used to raise thetemperature or otherwise change the conditions of bodily fluids toeffect release of the device. Additional variations allow for the use ofan exterior energy source to raise the temperature of the areasurrounding the device. For example, a patient can ingest a sufficientvolume of fluid, followed by the application of an external energysource (e.g., radiofrequency or ultrasound) to the exterior of thepatient's abdomen to warm the fluid within the stomach to the desiredT_(M). In another variation, the exogenous substance, e.g. elementalmagnesium, itself causes an exothermic reaction to occur in the stomach.

Yet another approach providing a exogenous substance 120 to anintragastric device comprising T_(M)=50° C. modified PCL is theingestion of 500 mL of alkaline solution (e.g. saturated sodiumbicarbonate) pre-warmed to 55° C. Said solution initiates an exothermicreaction upon neutralization with the stomach acid, warming the stomachcontents above the 50° C. PCL melting point.

Emptying and Deswelling Degradation

Certain embodiments of the present invention comprise a system for therapid degradation and volume reduction of an intragastrichydrogel-containing medical device. The system disclosed herein consistsof three paired materials: a degradable device structural element, ahydrogel and a tuned dissolution (or deswelling) solution selected todegrade the structural element and deswell the particular hydrogelaccording to their underlying chemical properties. The system isemployed in the following way: First, an intragastric device containinga hydrogel is swallowed, ingested or inserted into a patient's stomach.The hydrogel swells when exposed to fluid and takes up space within thestomach lumen. Following a sufficient residence time determined by thepatient or by an administering healthcare professional, a hydrogeldeswelling agent is ingested by or administered to the patient. Thedeswelling agent (which may be in the form of a solid, liquid, or gas)causes the device to release the enclosed hydrogel by degrading astructural element (a stitch, a line of stitches, a seam, a glue, apatch, a plug, or other known structural elements in the art). Thedeswelling agent then rapidly decreases the volume of the hydrogel tofacilitate pyloric passage and safe distal GI tract transit.

Numerous structural elements susceptible to degradation followingexposure to particular aqueous conditions are known in the art. Examplesinclude the polymer polycaprolactone which can be extruded into plaques,films, monofilaments, plugs, and other structural elements.Polycaprolactone (available from The DURECT Corporation, Birmingham,Ala.) has a melting temperature of approximately 60° C. and can bethermoformed, molded, or extruded into a number of structural elementsknown in the art. Modified PCL with melting temperatures ranging from˜40-60° C. (available from Zeus Industrial Products of Orangeburg, S.C.)can also be thermoformed, molded, or extruded into a number ofstructural elements known in the art.

Device structural elements can also be produced from materials thatselectively dissolve when exposed to elevated pH conditions, but remainsubstantially structurally intact when exposed to lower pH conditions.For example, stretch-drawn fibers can be produced from poly(methacrylicacid-co-methyl methacrylate), available as EUDRAGIT S-100, orpoly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid)co-polymer, available as EUDRAGIT FS-30D, both from Evonik Industries ofDarmstadt, Germany. These polymers can be formulated with Tri EthylCitrate (TEC) and extruded into filaments which can be used to close theseams of an intragastric device. For example, a 70% EUDRAGIT S-100 and30% Tri Ethyl Citrate (available from Samrudhi Pharmachem of Mumbai,India) mix can be blended and extruded into fiber using a single screwextruder. The resulting filament can then be used to sew a seam of anintragastric device filled with hydrogel. The resulting fiber and seamremain substantially structurally stable (for example, having mechanicalproperties such as strength which do not change over time) but rapidlydegrade (for example, by dissolving) at a pH greater than about 7.

Some hydrogels may be deswelled by exposure to an aqueous solutioncomprising elevated salt concentrations. FIG. 15 illustrates thisdeswelling effect and shows the degree of swelling for severalcross-linked polyacrylic acid and cross-linked polyacrylamide hydrogelsafter exposure to solutions containing various solutes at variousconcentrations. Each subject hydrogel was loaded into a permeablepolyester mesh pouch and exposed sequentially to the listedenvironments.

Pouches were created from 9.5 cm×22.0 cm pieces of polyester mesh(available as China Silk from Ryco of Lincoln, R.I.), folded in halfalong the long edge, closed along the long edge and one short edge withfabric glue (available as Bish's Tear Mender from True Value Hardware ofCambridge, Mass.), and filled with 1.0 gram of one of the followingsuperabsorbent hydrogels: Waste Lock 770 (available from M2 PolymerTechnologies, Inc.), Waste Lock PAM (available from M2 PolymerTechnologies, Inc.), Tramfloc 1001A (available from Tramfloc of Tempe,Ariz.), Water Crystal K (available from WaterCrystals.com), Hydrosource(available from Castle International Resources of Sedona, Ariz.),poly(acrylamide-co-acrylic acid) potassium salt (available fromSigma-Aldrich), and Soil Moist (available from JRM Chemical ofCleveland, Ohio). The pouches were closed along the remaining short edgewith three square knots of a polyester sewing thread, weighed, placed ina beaker filled with 350 mL tap water, and incubated at 37 C for 1 hour.The pouch was weighed after 30 minutes and 1 hour in tap water. Thepouch was then submerged in a beaker incubated at 37 C containing 350 mLof 2% sodium chloride, blended dog food (150 grams of Adult AdvancedFitness Dry Dog Food from Hill's Science Diet blended in 50 mL simulatedgastric fluid [2 grams sodium chloride, 3.2 grams pepsin, 7 mLhydrochloric acid, brought to 1 liter with tap water], and brought to 1L with tap water), pH 3 buffer (available as Hydrion pH 3 buffer fromMicro Essential Laboratory of Brooklyn, N.Y.), and 2.5% calcium chloridefor 3.5 hours each. In between each of these incubations, the poucheswere submerged in a beaker containing 350 mL tap water incubated at 37C.The pouch was weighed after each incubation. The pouches became lighterafter each incubation in the different media but regained most of theirmass after incubation in tap water. However, in 2.5% calcium chloride,each pouch lost a significant amount of mass and could not regain thismass after incubation in tap water (data not shown).

The hydrogels shown in FIG. 15A are comprised of either cross-linkedpolyacrylic acid or cross-linked polyacrylamide, materials that arewidely used in medical device applications. As evidenced by this data,administration of a deswelling solution comprised of 2.5% CalciumChloride could rapidly decrease hydrogel volume by ten times or more.Therefore, any of the hydrogels disclosed in FIG. 15A paired with a 2.5%Calcium Chloride deswelling solution constitute a system for ionicstrength-based construct degradation.

The hydrogels shown in FIG. 15B are comprised of either cross-linkedpolyacrylic acid or cross-linked polyacrylamide, materials that arewidely used in medical device applications. The composition andfabrication of this hydrogel is reported in the literature (Gemeinhart,et al., 2000). As evidenced from the data, swelling extent of thishydrogel rapidly increases above pH 3. This hydrogel is comprised ofhighly biocompatible materials and is therefore suitable for ingestionby a patient as part of a space occupation device. The hydrogel willswell in a normal gastric environment. When the device is ready to beeliminated, a low pH deswelling solution could be administered to thepatient to rapidly de-swell the hydrogel.

FIG. 15C depicts the swelling performance of a chitosan/poly(vinylalcohol) superporous hydrogel in solutions at different pHs. Thecomposition and fabrication of this hydrogel is reported in theliterature (Gupta, et al., 2010). As shown in the FIG. 15C, the swellingextent of this hydrogel rapidly decreases above pH 3. This hydrogel iscomprised of highly biocompatible materials and could be swallowed by apatient as part of a space occupation device. This hydrogel is swollenwith a solution at low pH (below 3). When the device is ready to beeliminated, an elevated pH deswelling solution (pH>3) is administered tothe patient to rapidly de-swell the hydrogel.

Exemplary Embodiment 1

One embodiment of the system for rapid hydrogel construct degradationcomprises a hydrogel-containing intragastric device and deswelling agentcapable of simultaneously opening the device and deswelling thehydrogel. The construct in this exemplary embodiment is fabricated usingthe following materials: Pouches are created from 9.5 cm×22.0 cm piecesof polyester mesh (available as China Silk from Ryco of Lincoln, R.I.),folded in half along the long edge, closed along the long edge and oneshort edge with fabric glue (available as Bish's Tear Mender from TrueValue Hardware of Cambridge, Mass.), and filled with 1.0 gram of WasteLock 770 hydrogel (available from M2 Polymer Technologies, Inc.). Thepouch(es) are closed along the remaining short edge with, for example,three square knots of modified Polycaprolactone thread (available fromZeus Industrial Products of Orangeburg, S.C.) processed to melt at 47°C. The corresponding dissolution solution comprises a 2.5% CalciumChloride aqueous solution heated to 55° C. This solution degrades themodified polycaprolactone structural element (knots holding the pouchesclosed) and deswells the salt-sensitive hydrogel.

The invention claimed is:
 1. A medical device for use with a fluidfiller material and for occupying a space within a patient's body, themedical device comprising: a first fluid impermeable surface materialforming a device body having an interior reservoir, the device bodyhaving a deployment profile and expandable to an active profile uponreceiving the fluid filler material within the interior reservoir; afluid tunnel ending within the interior reservoir; and a release channelformed by an interior of a second fluid impermeable material, where therelease channel is in fluid communication with the interior reservoirand is temporarily fluidly sealed by a release material located in theinterior reservoir about an exterior of the second fluid impermeablematerial to mechanically secure the second fluid impermeable material tofluidly seal the release channel and to prevent fluid transfer to orfrom the patient's body until the fluid filler material reduces thestructural integrity of the release material to unseal the releasechannel.
 2. The device of claim 1, where the fluid impermeable materialforming the release channel comprises a portion of the surface material.3. The device of claim 2, where the second fluid impermeable materialforming the release channel comprises at least two layers of the secondfluid impermeable surface sealed along at least one edge.
 4. The deviceof claim 1, where the second fluid impermeable material forming therelease channel comprises a tapered shape.
 5. The device of claim 1,where the second fluid impermeable material forming the release channeland the first fluid impermeable surface material are joined together. 6.The device of claim 1, where upon the addition of the fluid fillermaterial to the interior reservoir the release material begins tostructurally degrade to unseal the release channel.
 7. The device ofclaim 1, where the release channel includes an axis and where the secondfluidly impermeable material is twisted about the axis prior to beingtemporarily restrained.
 8. The device of claim 7, further comprising anenergy storage element located within the release channel, where theenergy storage element is restrained by the release material in acompressed configuration.
 9. The device of claim 8, where the energystorage element comprises an elastically resilient member, on release ofthe temporary restraint, the elastically resilient member expands therelease channel.
 10. The device of claim 1, further comprising at leastone suture member, where the at least one suture member mechanicallycouples a fluid conduit to at least one wall of the fluid tunnel. 11.The device of claim 10, where the suture is coupled to at least oneweakened section of the wall of the fluid tunnel such that applying aproximal force on the suture member detaches the weakened section fromthe wall of the fluid tunnel to decouple the fluid tunnel from the fluidconduit.
 12. The device of claim 10, where the conduit is coupled to atleast one weakened section of the wall of the fluid tunnel such thatapplying a tensile force on the conduit detaches the weakened sectionfrom the wall of the fluid tunnel to decouple the conduit from the fluidtunnel.
 13. The device of claim 10, further comprising a swellablematerial located between the fluid tunnel and the fluid conduit.
 14. Amedical device for use with a fluid filler material and for occupying aspace within a patient's body, the medical device comprising: a devicebody having an interior reservoir, the device body having a deploymentprofile and being expandable to an active profile upon addition of thefluid filler material into the interior reservoir; a valve extendingwithin the interior reservoir, the valve being pre-disposed to obstructfluid flow therethrough; and a fluid passage formed by an interior asection of material, where the fluid passage is in fluid communicationwith the interior reservoir and where the section of material istemporarily mechanically closed from an exterior of the section ofmaterial to fluidly seal the fluid passage to prevent fluid transferbetween the interior reservoir and the patient's body until the fluidfiller reduces the structural integrity of a segment of a releasematerial to unseal the fluid passage, where the segment of the releasematerial is located in the interior reservoir and does not extend intothe fluid passage.
 15. The device of claim 14, where the section ofmaterial comprises a tapered shape.
 16. The device of claim 14, wherethe device body is formed from a fluid impermeable surface material andwhere the section of material is joined with the fluid impermeablesurface material.
 17. The device of claim 14, where the release materialcomprises a rate of hydrolysis that causes degradation of the releasematerial after a predetermined time of at least two weeks.
 18. Thedevice of claim 14, where on the addition of the fluid filler materialto the interior reservoir, the release material structurally degradessufficiently to release the section of material from restraint.
 19. Thedevice of claim 14, where the fluid passage includes an axis and wherethe section of material is twisted about the axis prior to beingtemporarily restrained.
 20. The device of claim 14, where the section ofmaterial is folded about the axis prior to being temporarily restrained.21. The device of claim 14, further comprising an energy storage elementlocated within the fluid passage, where the energy storage element isrestrained by a temporary restraint in a compressed configuration. 22.The device of claim 14, further comprising at least one suture member,where the at least one suture member mechanically couples a fluidconduit to the valve.
 23. The device of claim 22, where at least a firstend of the suture member extends to a proximal end of the fluid conduit.24. The device of claim 23, where the first and a second end of thesuture member extends to the proximal end of the fluid conduit, and amiddle portion of the suture member mechanically couples the fluidconduit to the valve, where pulling on the first or second end of thesuture member decouples the fluid conduit from the valve.
 25. The deviceof claim 22, where the suture is detachably coupled to the valve suchthat applying a proximal force on the suture member detaches theweakened section from the valve to decouple the valve from the fluidconduit.
 26. The device of claim 22, further comprising a swellablematerial located between the valve and the fluid conduit.
 27. A medicaldevice for use with a fluid filler material for occupying a space withina patient's body, the medical device comprising: a device body having aninterior reservoir, the device body having a deployment profile and uponreceiving the fluid filler material expands to an active profile; avalve within the interior reservoir, the valve being pre-disposed toobstruct flow therethrough; a release material; and a fluid passageformed by a section of material, where the section of material extendsinward into and is temporarily restrained within the reservoir by asection of the release material that is located within the reservoir andexterior to the fluid passage, wherein when temporarily restrained,fluid is prevented from passing from the reservoir through the fluidpassage and into the patient's body, and where degradation of thesection of the release material frees the section of material fromrestraint to permit opening of the fluid passage to allow egression offluids from the interior reservoir.
 28. The device of claim 1, where afluid conduit having a distal portion disposed within the fluid tunnelto create a fluid path through the fluid tunnel for delivery of thefluid filler material into the interior reservoir.